Vehicle steering hydraulic control system and method

Abstract

The application discloses a kind of vehicle steering hydraulic control system and method, the control system includes hydraulic oil tank, engine, pump group, full hydraulic steering gear, steering drive mechanism, rear wheel drive mechanism, control valve group and oil circuit system.The control system is adjusted by control valve group and oil circuit system the specific path and pressure of the hydraulic oil flow to front wheel steering drive mechanism and rear wheel drive mechanism, realize front wheel steering, rear wheel drive and in-place steering.Front wheel steering drive mechanism adopts steering cylinder, floating cylinder and steering knuckle design, through slider and block locking cylinder rod.Control valve group adjusts floating cylinder locking state and rear wheel drive direction.Oil circuit system includes multiple oil circuits, ensure the effective circulation and control of hydraulic oil.The system has the advantages of accurate adjustment, fast response, improve steering efficiency and reduce energy consumption, enhance system stability and reliability, flexible adaptation to various working conditions and simplify operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic control, and particularly to a vehicle steering hydraulic control system and method. BACKGROUND

[0002] In the context of the continuous evolution of vehicle technology and the increasing demand for vehicle handling performance, dual-mode steering systems have become an important trend in the innovation of modern vehicle steering systems due to their ability to flexibly adjust steering modes according to changing driving conditions and specific needs of drivers. In the prior art, such as the dual-mode steering system and vehicle design disclosed in Chinese patent document CN117262003A, through innovative mechanical structure and connection layout, the free rotation function of the front wheels and the precise steering mechanism based on the kingpin are successfully realized. This system ingeniously combines the collaborative work of floating cylinders and steering cylinders, and with the help of precise monitoring by displacement sensors, ensures the accuracy of steering operation and the stability of the system.

[0003] Although the CN117262003A patent has made significant achievements in mechanical structure design, it mainly focuses on the innovation of physical structure, and the control method for realizing the efficient operation of this complex mechanical system is not elaborated. Based on the mechanical architecture shown in CN117262003A, a key challenge for current technology is how to develop a control strategy that matches it to fully exploit the potential of the dual-mode steering system.

[0004] Traditional hydraulic control systems are generally limited to providing a single assist mode, making it difficult to meet the high requirements of dual-mode steering systems for flexibility and response speed. During mode switching, such systems often have response delays, reduced control accuracy, and increased energy consumption, which seriously restricts the further improvement of vehicle handling performance. In addition, existing hydraulic control systems also have obvious shortcomings in accurately regulating steering force, improving steering efficiency, and energy saving and emission reduction, making it difficult to meet the urgent needs of modern vehicles for high efficiency and environmental protection.

[0005] In view of the above problems, the present application aims to fill the gap in the existing technology in the hydraulic control method of dual-mode steering systems by designing a set of hydraulic control devices and control methods specifically designed for dual-mode steering systems. SUMMARY

[0006] The technical problems to be solved by the present application are to overcome the above technical defects, provide a vehicle steering hydraulic control system and method, and overcome the limitations of traditional hydraulic control systems in mode switching, precise control and energy consumption management. The core of the present application is to optimize the hydraulic control strategy, realize precise adjustment of the steering force and rapid and smooth switching of the steering mode, and thus comprehensively improve the control performance, driving stability and fuel economy of the vehicle, and lay a solid foundation for the wide application of the dual-mode steering system

[0007] To solve the above technical problems, the technical scheme provided by the present application is as follows: a vehicle steering hydraulic control system, comprising:

[0008] a hydraulic oil tank for storing and providing hydraulic oil;

[0009] an engine having a plurality of power take-off ports at its output end for providing hydraulic power for front wheel steering and rear wheel driving;

[0010] a pump group comprising steering master pump one and steering master pump two connected to one of the power take-off ports of the engine, and rear wheel master pump one and rear wheel master pump two connected to the other power take-off port of the engine, for converting the power of the engine into hydraulic energy;

[0011] a full hydraulic steering gear whose valve core is driven to rotate by the steering wheel, for realizing steering control;

[0012] a steering drive mechanism for controlling the front wheel steering of the vehicle;

[0013] a rear wheel drive mechanism comprising a left hydraulic motor for driving the left rear wheel of the vehicle and a right hydraulic motor for driving the right rear wheel of the vehicle;

[0014] a control valve group for adjusting the path and pressure of the hydraulic oil flow to realize different steering and driving modes;

[0015] an oil circuit system for connecting the hydraulic oil tank, pump group, full hydraulic steering gear, steering drive mechanism, rear wheel drive mechanism and control valve group to control the circulation and path of the hydraulic oil;

[0016] Wherein, the system can adjust the specific path and pressure of the hydraulic oil flow to the front wheel steering drive mechanism and the rear wheel drive mechanism through the control valve group and the oil circuit system according to the operation of the driver and the preset steering mode, so as to realize the front wheel steering, the rear wheel driving and the in-place steering of the vehicle.

[0017] Preferably, the front wheel steering drive mechanism comprises a steering oil cylinder, a left floating oil cylinder, a right floating oil cylinder, a left front wheel mounting frame and a right front wheel mounting frame, the left front wheel mounting frame and the right front wheel mounting frame each comprise a steering knuckle, the steering knuckle is arranged on the frame through a kingpin, the steering oil cylinder is provided with two output ends and is rotatably connected with the cylinder barrels of the left floating oil cylinder and the right floating oil cylinder respectively, and the cylinder rods of the left floating oil cylinder and the right floating oil cylinder are rotatably connected with the steering rocker arms on the same side respectively.

[0018] Preferably, the middle part of the inner cavities of the left floating oil cylinder and the right floating oil cylinder is provided with a stopper, the stopper divides the cylinder barrel inner cavity into a rod cavity, a rodless cavity and a middle cavity, a sliding block is slidably arranged in each of the rod cavity and the rodless cavity, and the sliding blocks are used to move towards each other under the action of the hydraulic oil so as to lock the cylinder rod.

[0019] Preferably, the control valve group comprises a control valve one, a control valve two, a control valve three and a control valve four, the control valve one and the control valve two are used to adjust the locking state of the cylinder rods of the left floating oil cylinder and the right floating oil cylinder, and the control valve three and the control valve four are used to control the driving direction of the rear wheel drive mechanism.

[0020] Preferably, the oil path system further comprises:

[0021] A first oil path is led out from the hydraulic oil tank, connected to the oil injection ports of the steering master pump one and the steering master pump two, and used to provide the hydraulic oil for the steering master pump one and the steering master pump two;

[0022] A first oil path is led out from the hydraulic oil tank, connected to the oil injection ports of the steering master pump one and the steering master pump two, and used to provide the hydraulic oil for the steering master pump one and the steering master pump two;

[0023] A first oil path is led out from the hydraulic oil tank, connected to the oil injection ports of the steering master pump one and the steering master pump two, and used to provide the hydraulic oil for the steering master pump one and the steering master pump two;

[0024] A first oil path is led out from the hydraulic oil tank, connected to the oil injection ports of the steering master pump one and the steering master pump two, and used to provide the hydraulic oil for the steering master pump one and the steering master pump two;

[0025] A first oil path is led out from the hydraulic oil tank, connected to the oil injection ports of the steering master pump one and the steering master pump two, and used to provide the hydraulic oil for the steering master pump one and the steering master pump two;

[0026] A first oil path is led out from the hydraulic oil tank, connected to the oil injection ports of the steering master pump one and the steering master pump two, and used to provide the hydraulic oil for the steering master pump one and the steering master pump two;

[0027] The second oil path is drawn from the hydraulic oil tank and connected to the oil inlet of the rear wheel main pump one and the rear wheel main pump two, and provides hydraulic oil for the rear wheel main pump one and the rear wheel main pump two;

[0028] The E oil path is drawn from the oil outlet end of the rear wheel main pump one, connected to the control valve three and the left hydraulic motor respectively, and finally returns to the hydraulic oil tank, forming the oil path circulation of the left rear wheel drive;

[0029] The F oil path is drawn from the oil outlet end of the rear wheel main pump two, connected to the control valve four and the right hydraulic motor respectively, and finally returns to the hydraulic oil tank, forming the oil path circulation of the right rear wheel drive.

[0030] Preferably, the first oil path and the second oil path are both provided with an oil suction filter.

[0031] Preferably, a pressure relief oil path is arranged between the oil inlet branch and the D oil path, and a pressure relief valve is arranged on the pressure relief oil path.

[0032] In another aspect, the application also provides a steering control method, comprising the following specific steps:

[0033] Step A: system initialization and default steering mode one setting

[0034] After starting the vehicle, the system defaults to steering mode one;

[0035] At this time, the control valve one and the control valve two are both in a non-powered state, and the hydraulic control check valve remains in its default closed state, in which the hydraulic control check valve is unidirectional flow and can prevent the hydraulic oil from flowing backward;

[0036] Start the steering main pump two, and inject the hydraulic oil into the rod cavity and the rodless cavity of the left floating oil cylinder and the right floating oil cylinder through the B oil path, the C oil path and the oil inlet branch;

[0037] In mode two, the sliders in the left floating oil cylinder and the right floating oil cylinder move towards each other under the action of the hydraulic oil and push the cylinder rod to move to the middle until they are fixed by the stopper, the hydraulic oil squeezed out of the cylinder barrel of the left floating oil cylinder and the right floating oil cylinder returns to the hydraulic oil tank through the D oil path, and in mode two, the hydraulic control check valve is in a closed state, so the hydraulic oil in the rod cavity and the rodless cavity cannot flow backward through the oil inlet branch, thereby ensuring the locking and fixing of the cylinder rod position, and in this state, the left floating oil cylinder and the right floating oil cylinder are only used as connecting rods of the front wheel steering drive mechanism, and in this state, the control valve three and the control valve four are not powered, the rotation speed of the left hydraulic motor and the right hydraulic motor is controlled by the accelerator, and the vehicle speed is increased according to the depth of the accelerator pedal;

[0038] Step B: front wheel steering control in steering mode two

[0039] Left steering: the driver rotates the steering wheel to the left, the valve core of the full hydraulic steering gear shifts, the pressure oil is pushed to the left cavity of the steering oil cylinder through the A oil way, the cylinder rod of the steering oil cylinder slides to the right, the left and right floating oil cylinders slide to the right, and the left and right front wheel mounts and the front tires rotate to the left through the mechanical linkage of the steering rocker arm, so that the left steering is realized;

[0040] Right steering: similarly, the driver rotates the steering wheel to the right, the valve core of the full hydraulic steering gear shifts, the pressure oil is pushed to the right cavity of the steering oil cylinder, the cylinder rod of the steering oil cylinder slides to the left, and the right steering is realized;

[0041] Step C: entering steering mode two and preparing for spot steering

[0042] Before the driver selects to enter steering mode two by operating the button, the controller needs to detect the vehicle speed and the steering wheel angle to determine whether the entering condition is met; if the condition is met, the controller controls the rotation speed of the left and right hydraulic motors according to the vehicle speed and the steering wheel angle to obtain a reasonable steering radius; the specific control logic is to calculate the tire angle according to the steering wheel angle, and then to calculate the rotation speed ratio of the rear driving wheels according to the angle to control the rotation speed of the left and right hydraulic motors;

[0043] After starting the vehicle, the driver selects to enter mode two by pressing the button, first determines whether the left and right hydraulic motors are less than the target value, if not, it still enters steering mode one; if it is met, it further determines whether the steering wheel angle is less than the target value, if not, it still enters steering mode one; if it is met, the control valve one and the control valve two are powered on, and the pressure oil is injected into the control port of the hydraulic control one-way valve through the control oil way and the control oil distribution way, so that the one-way flow function is lost, and the hydraulic oil is allowed to flow back to the hydraulic oil tank, at this time, the left and right floating oil cylinders can change freely within a certain range, and the preparation for spot steering is made;

[0044] Step D: spot steering control in steering mode two

[0045] Left spot steering: the driver rotates the steering wheel to the left, the control valve three is powered on to make the left hydraulic motor rotate reversely, and the control valve four is not powered on to make the right hydraulic motor rotate forward; the left rear tire moves backward, and the right rear tire moves forward; since the front wheels are in a floating state and have a traction angle, the front wheels automatically adjust the direction according to the rotation speed difference of the rear wheels to realize left spot steering;

[0046] Right spot steering: the driver rotates the steering wheel to the right, the control valve four is powered on to make the right hydraulic motor rotate reversely, and the left hydraulic motor rotates forward to realize right spot steering;

[0047] Step E: mode switching and recovery

[0048] When the driver needs to switch back to steering mode one, by operating the button selection, both control valve one and control valve two are powered off, the hydraulic control check valve restores the one-way flow function, the cylinder rods of the left and right floating oil cylinders are locked and fixed again, and the system returns to the state of steering mode one.

[0049] The present application significantly optimizes the performance of the dual-mode steering system by proposing a hydraulic control device specifically for the dual-mode steering system and its control method. Compared with the prior art, the main advantages of the present application are reflected in the following aspects:

[0050] Precise adjustment and fast response: The hydraulic control device of the present application realizes precise adjustment of steering force and fast switching of steering mode through optimization of hydraulic control strategy. This precision ensures stability and handling performance of the vehicle under different driving conditions and driving demands, improving safety and comfort of driving.

[0051] Improving steering efficiency and reducing energy consumption: Through the carefully designed oil circuit system and control valve group, the present application can more effectively utilize hydraulic energy and reduce energy loss. This not only improves the efficiency of the steering system, but also significantly reduces the energy consumption of the vehicle, meeting the requirements of modern vehicles for energy saving and emission reduction.

[0052] Enhancing system stability and reliability: The steering control system of the present application uses the synergistic effect of floating oil cylinders and steering oil cylinders, as well as the precise detection of displacement sensors, to ensure the accuracy and stability of steering. At the same time, safety measures such as pressure relief valves and oil suction filters in the oil circuit system further enhance the reliability and durability of the system.

[0053] Flexible adaptation to various working conditions: The steering control system of the present application can accurately regulate the flow path and pressure of hydraulic oil to the front wheel steering drive mechanism and rear wheel drive mechanism according to the driver's operation and preset steering mode through the control valve group and oil circuit system. This flexibility enables the vehicle to easily cope with different driving environments and operating requirements, such as stability requirements at high speed and fast steering requirements during harvesting operations.

[0054] Simplify operation and improve user experience: The steering control method of the present application is simple and easy to understand, and the driver only needs to switch the steering mode through the operating button without complicated operation process. This convenience not only improves the driving experience, but also reduces the difficulty of operation and the risk of misoperation.

[0055] In summary, the present application optimizes the hydraulic control strategy, improves the design of the oil circuit system and control valve group, and provides a flexible steering control method, which significantly improves the performance advantages of the dual-mode steering system, solves the shortcomings of the prior art, and provides a more stable, efficient, energy-saving and flexible steering solution for modern vehicles. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 is the overall schematic diagram of the vehicle steering hydraulic control system of the present application.

[0057] Figure 2 is the internal structure schematic diagram of the left floating oil cylinder in the present application.

[0058] Figure 3 is the partial schematic diagram of the left steering control in the steering mode one state of the present application.

[0059] Figure 4 is the partial schematic diagram of the right steering control in the steering mode one state of the present application.

[0060] Figure 5 is the partial schematic diagram of the left zero-radius steering control in the steering mode two state of the present application.

[0061] Figure 6 is the partial schematic diagram of the right zero-radius steering control in the steering mode two state of the present application.

[0062] Figure 7 is the switching logic control schematic diagram of the steering mode one and the steering mode two in the present application.

[0063] Figure 8 is the logic control schematic diagram of the left hydraulic motor reverse and the right hydraulic motor reverse in the steering mode two state of the present application.

[0064] Figure 9 is the structure schematic diagram of the left front wheel mounting frame in the present application.

[0065] As shown in the figure: 1, hydraulic oil tank, 2, engine, 3, control oil distribution path, 4, steering master pump one, 5, steering master pump two, 6, rear wheel master pump one, 7, rear wheel master pump two, 8, full hydraulic steering gear, 9, steering wheel, 10, left hydraulic motor, 11, right hydraulic motor, 12, steering oil cylinder, 13, left floating oil cylinder, 14, right floating oil cylinder, 15, steering knuckle, 16, kingpin, 17, steering rocker arm, 18, stop block, 19, rod cavity, 20, rodless cavity, 21, middle cavity, 22, sliding block, 23, control valve one, 24, control valve two, 25, control valve three, 26, control valve four, 27, first oil path, 28, A oil path, 29, B oil path, 30, C oil path, 31, oil inlet branch, 32, hydraulic control check valve, 33, D oil path, 34, control oil path, 35, second oil path, 36, E oil path, 37, F oil path, 38, oil suction filter, 39, pressure relief oil path, 40, pressure relief valve. DETAILED DESCRIPTION

[0066] The application will be described in further detail below with reference to the drawings.

[0067] The specific embodiments of the application will be further described below with reference to the drawings. Identical parts are denoted by identical reference numerals.

[0068] It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings, and the words "inner" and "outer" refer to the directions towards or away from the geometric center of a particular component.

[0069] In order to make the content of the application more easily understood, the technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings of the embodiments of the application.

[0070] Referring to the drawings Figure 1 - the drawings Figure 4 and the drawings Figure 9 A vehicle steering hydraulic control system, the core components of which include: a hydraulic oil tank 1, which serves as a storage and supply source for hydraulic oil; an engine 2, which provides power for front wheel steering and rear wheel driving; a pump group, which is composed of a steering master pump one 4 and a steering master pump two 5 connected to one of the power take-off ports of the engine 2, and a rear wheel master pump one 6 and a rear wheel master pump two 7 connected to the other power take-off port of the engine 2, which is responsible for converting the power of the engine 2 into hydraulic energy; a full hydraulic steering gear 8, the valve core of which rotates in response to the operation of a steering wheel 9, realizing the input of steering instructions; a steering drive mechanism, which is responsible for executing the front wheel steering action; a rear wheel driving mechanism, which includes a left hydraulic motor 10 and a right hydraulic motor 11, which respectively drive the left rear wheel and the right rear wheel of the vehicle; a control valve group, which flexibly adjusts the hydraulic oil flow path and pressure to meet different steering and driving requirements; and an oil circuit system, which serves as the blood vessels connecting the components, ensuring the circulation and path control of the hydraulic oil. The steering control system can accurately regulate the path and pressure of the hydraulic oil flowing to the front wheel steering drive mechanism and the rear wheel driving mechanism according to the driver's instructions and the preset steering mode, realizing the complex functions of front wheel steering, rear wheel driving and even spot steering.

[0071] In one embodiment, the front wheel steering drive mechanism is the core part of the entire steering control system. It includes a steering cylinder 12, a left floating cylinder 13, a right floating cylinder 14, a left front wheel mounting bracket and a right front wheel mounting bracket. The left front wheel mounting bracket and the right front wheel mounting bracket are both rotationally connected on the frame through a steering knuckle 15 and a kingpin 16, which allows the front wheels to flexibly perform steering operations under the drive of the steering wheel 9.

[0072] The steering cylinder 12 has two output ends, which are respectively connected with the cylinder barrels of the left floating cylinder 13 and the right floating cylinder 14. When the steering wheel 9 rotates, the full hydraulic steering gear 8 adjusts the flow direction and pressure of the hydraulic oil according to the rotation angle and direction of the steering wheel 9, thereby driving the cylinder rod of the steering cylinder 12 to extend or retract. The extension or retraction of the cylinder rod of the steering cylinder 12 further pushes the cylinder rods of the left floating cylinder 13 and the right floating cylinder 14, and through the mechanical linkage relationship of the steering rocker arm 17, finally drives the left and right front wheel mounts and the front tires thereon to steer.

[0073] In addition, the left floating cylinder 13 and the right floating cylinder 14 are also designed very ingeniously. The inner cavities of their cylinder barrels are divided into rod cavities 19, rodless cavities 20 and middle cavities 21 by the stopper 18. In the rod cavities 19 and the rodless cavities 20, the sliding blocks 22 can move close to each other under the action of the hydraulic oil, thereby locking the cylinder rods. This design not only improves the stability of the steering system, but also ensures the accuracy and reliability of the front wheels during steering.

[0074] In another embodiment, the control valve group includes control valve one 23, control valve two 24, control valve three 25 and control valve four 26. These control valves achieve precise control over the front wheel steering drive mechanism and the rear wheel drive mechanism by precisely adjusting the flow direction and pressure of the hydraulic oil. Control valve one 23 and control valve two 24 are mainly responsible for adjusting the locking state of the cylinder rods of the left floating cylinder 13 and the right floating cylinder 14. When the cylinder rods need to be locked, they adjust the flow direction and pressure of the hydraulic oil to make the sliding blocks 22 close to each other and lock the cylinder rods. When the cylinder rods need to be released, they adjust the flow direction and pressure of the hydraulic oil to make the sliding blocks 22 separate from each other and release the cylinder rods. Control valve three 25 and control valve four 26 are responsible for controlling the driving direction of the rear wheel drive mechanism. They achieve precise control over the speed and direction of the left hydraulic motor 10 and the right hydraulic motor 11 by adjusting the flow direction and pressure of the hydraulic oil. This control function enables the vehicle to be flexibly adjusted according to the driver's operation and the preset driving mode, thereby meeting the driving requirements in different working conditions.

[0075] Further, the layout and functional design of the oil circuit system are very ingenious. It includes the first oil circuit 27 and the second oil circuit 35 drawn from the hydraulic oil tank 1, which are respectively responsible for providing hydraulic oil for the steering master pump one 4, the steering master pump two 5, and the rear wheel master pump one 6, the rear wheel master pump two 7.

[0076] A oil circuit 28 is drawn from the oil outlet end of the steering master pump one 4, connected to the full hydraulic steering gear 8, the steering cylinder 12 in turn, and finally flows back to the hydraulic oil tank 1, forming the main oil circuit circulation of the steering control. B oil circuit 29 is drawn from the oil outlet end of the steering master pump two 5, connected to control valve one 23 and control valve two 24 respectively, providing power source for the hydraulic oil circuit of the steering mode.

[0077] C oil circuit 30 is provided on the outlet end of control valve one 23, and is led out from the control valve one 23, and a plurality of oil inlet branches 31 are provided on the C oil circuit 30 and are communicated with the rod cavity 19 and the rodless cavity 20. A hydraulic control check valve 32 is provided on each oil inlet branch 31, which is used to control the flow direction of the hydraulic oil and lock the position of the cylinder rod of the left floating cylinder 13 and the right floating cylinder 14. The D oil circuit 33 is led out from the middle cavity 21 and is connected to the hydraulic oil tank 1, which is used to return the hydraulic oil squeezed out from the cylinder barrel of the left floating cylinder 13 and the right floating cylinder 14 to the hydraulic oil tank 1.

[0078] In addition, the control oil circuit 34 is provided on the outlet end of the control valve two 24, and is led out from the control valve two 24, and a plurality of control oil branches 3 are provided on the control oil circuit 34 and are connected to the hydraulic control check valve 32. These control oil branches 3 are used to control the opening and closing of the hydraulic control check valve 32, so as to realize flexible switching of the cylinder rod locking state.

[0079] In order to improve the safety and reliability of the oil circuit system, the oil suction filter 38 is arranged on the first oil circuit 27 and the second oil circuit 35, which effectively prevents impurities and pollutants from entering the hydraulic system. At the same time, the pressure relief oil circuit 39 is arranged between the oil inlet branch 31 and the D oil circuit 33 and is equipped with a pressure relief valve 40. When the system pressure exceeds the set value, the pressure relief valve 40 will automatically open, and the excess hydraulic oil will be released back to the hydraulic oil tank 1, so as to protect the safety of the system.

[0080] On the other hand, the application also provides a steering control method, which comprises the following specific steps:

[0081] Step A: system initialization and default steering mode one setting

[0082] After starting the vehicle, the system defaults to steering mode one;

[0083] At this time, the control valve one 23 and the control valve two 24 are both in a non-powered state, and the hydraulic control check valve 32 remains in its default closed state. In this state, the hydraulic control check valve 32 is unidirectional, which can prevent the hydraulic oil from flowing backward;

[0084] Start the steering master pump two 5, and inject the hydraulic oil into the rod cavity 19 and the rodless cavity 20 of the left floating cylinder 13 and the right floating cylinder 14 through the B oil circuit 29, the C oil circuit 30 and the oil inlet branch 31;

[0085] In the mode, the slider 22 in the left floating oil cylinder 13 and the right floating oil cylinder 14 is close to each other under the action of hydraulic oil and pushes the cylinder rod to move to the middle until it is fixed by the stopper 18, the hydraulic oil squeezed out of the cylinder barrel of the left floating oil cylinder 13 and the right floating oil cylinder 14 returns to the hydraulic oil tank 1 through the D oil way 33, in the mode, the hydraulic control check valve 32 is in the closed state, therefore, the hydraulic oil in the rod cavity 19 and the rodless cavity 20 cannot flow backward through the oil inlet branch 31, so as to ensure the locking and fixing of the cylinder rod position, the left floating oil cylinder 13 and the right floating oil cylinder 14 are only used as the connecting rod of the front wheel steering drive mechanism in this state, and the control valve three 25 and the control valve four 26 cannot be electrified in this state, the rotation speed of the left hydraulic motor 10 and the right hydraulic motor 11 is controlled by the oil door, and the vehicle speed is increased according to the depth of the oil door pedal;

[0086] Step B: front wheel steering control in the mode

[0087] Left steering: the driver rotates the steering wheel 9 to the left, the valve core of the full hydraulic steering gear 8 is rotated, the pressure oil is pushed to the left cavity of the steering oil cylinder 12 through the A oil way 28, the cylinder rod of the steering oil cylinder 12 is driven to slide to the right, the left floating oil cylinder 13 and the right floating oil cylinder 14 are driven to slide to the right, and then the left front wheel mounting frame, the right front wheel mounting frame and the front tire are turned to the left side through the mechanical linkage relationship of the steering rocker arm 17, so as to realize left steering.

[0088] Right steering: similarly, the driver rotates the steering wheel 9 to the right, the valve core of the full hydraulic steering gear 8 is rotated, and the pressure oil is pushed to the right cavity of the steering oil cylinder 12, so as to drive the cylinder rod of the steering oil cylinder 12 to slide to the left, thereby realizing right steering.

[0089] Step C: entering the steering mode two and preparing for the spot steering

[0090] Referring to the accompanying drawings Figure 5 - the accompanying drawings Figure 8 Before the driver selects to enter the steering mode two by operating the button, the controller needs to detect the vehicle running speed and the steering wheel angle, and judge whether the entering condition is met. If the condition is met, the controller controls the rotation speed of the left and right hydraulic motors 10 and 11 according to the running speed and the steering wheel angle, so as to obtain a reasonable steering radius. The specific control logic is that the tire angle is calculated according to the steering wheel 9 angle, and then the target rotation speed of the rear driving wheel is calculated according to the angle, so as to control the rotation speed of the left and right hydraulic motors 10 and 11. The total angle of the steering wheel 9 to the left and right side is x, the real-time angle of the steering wheel 9 is x 实时 , the left hydraulic motor 10 rotation speed is positive, and the right hydraulic motor 11 rotation speed is negative, the left hydraulic motor 10 rotation speed is β 左 , the right hydraulic motor 11 rotation speed is β 右 , and the design target vehicle speed is a. Therefore, when the steering wheel 9 is steered, the rotation speed of the left and right hydraulic motors 10 and 11 is:

[0091]

[0092]

[0093] After starting the vehicle, the driver selects mode two by pressing the button, first determines whether the left hydraulic motor 10 and the right hydraulic motor 11 are less than the target value, if not, it is still in steering mode one; if it is, it is further determined whether the steering wheel angle is less than the target value, if not, it is still in steering mode one; if it is, the control valve one 23 and the control valve two 24 are powered on, and the control oil way 34 and the control oil way 3 inject pressure oil to the control port of the hydraulic control check valve 32, so that it loses the function of one-way flow, allowing the hydraulic oil to flow back to the hydraulic oil tank 1, at this time, the left floating oil cylinder 13 and the right floating oil cylinder 14 can change within a certain range, preparing for the steering in place;

[0094] Step D: steering mode two steering in place control

[0095] Left steering in place: the driver rotates the steering wheel 9 to the left, the control valve three 25 is powered on, the left hydraulic motor 10 rotates in reverse, the control valve four 26 is not powered on, and the right hydraulic motor 11 rotates forward; the left rear tire travels backward, and the right rear tire travels forward; since the front wheels are in a floating state and have a traction angle, the front wheels automatically adjust the direction according to the speed difference of the rear wheels, realizing left steering in place;

[0096] Right steering in place: the driver rotates the steering wheel 9 to the right, the control valve four 26 is powered on, the right hydraulic motor 11 rotates in reverse, and the left hydraulic motor 10 rotates forward, realizing right steering in place.

[0097] Step E: mode switching and recovery

[0098] When the driver needs to switch back to steering mode one, the control valve one 23 and the control valve two 24 are both powered off by operating the button, the hydraulic control check valve 32 restores the one-way flow function, the cylinder rod of the left floating oil cylinder 13 and the right floating oil cylinder 14 is locked and fixed again, and the system returns to the state of steering mode one.

[0099] When the vehicle is running at high speed, the steering mode one is used to ensure the stability of the vehicle running at high speed and prevent the tire from deflecting when braking; when harvesting, the steering mode two is used to obtain a smaller turning radius and quickly complete a U-turn, which can improve the harvesting speed.

[0100] The above describes the present application and its embodiments, which are not limited, and the drawings only show one of the embodiments of the present application, and the actual structure is not limited thereto. In general, if a person skilled in the art is inspired thereby, without departing from the purpose of the present application, without creative design, similar structure and embodiments of the technical solution are not creative, and should belong to the protection scope of the present application.

Claims

1. A vehicle steering hydraulic control system characterized by comprising: The hydraulic control system for vehicle steering comprises: a hydraulic oil tank (1) for storing and providing hydraulic oil; an engine (2) having a plurality of power take-off ports at its output end for providing hydraulic power for front wheel steering and rear wheel driving; a pump set comprising a steering master pump one (4) and a steering master pump two (5) connected to one of the power take-off ports of the engine (2) and a rear wheel master pump one (6) and a rear wheel master pump two (7) connected to another power take-off port of the engine (2) for converting the power of the engine (2) into hydraulic energy; a full hydraulic steering gear (8) having a valve core driven to rotate by a steering wheel (9) for realizing steering control; a steering driving mechanism for controlling the steering of the front wheels of the vehicle; a rear wheel driving mechanism comprising a left hydraulic motor (10) for driving the left rear wheel of the vehicle and a right hydraulic motor (11) for driving the right rear wheel of the vehicle; a control valve set for adjusting the path and pressure of the hydraulic oil flow to realize different steering and driving modes; an oil circuit system for connecting the hydraulic oil tank (1), the pump set, the full hydraulic steering gear (8), the steering driving mechanism, the rear wheel driving mechanism and the control valve set to control the circulation and path of the hydraulic oil; wherein the hydraulic control system for vehicle steering can adjust the specific path and pressure of the hydraulic oil flow to the front wheel steering driving mechanism and the rear wheel driving mechanism through the control valve set and the oil circuit system according to the operation of the driver and the preset steering mode, so as to realize the front wheel steering, the rear wheel driving and the spot steering of the vehicle; the front wheel steering driving mechanism comprises a steering oil cylinder (12), a left floating oil cylinder (13), a right floating oil cylinder (14), a left front wheel mounting frame and a right front wheel mounting frame, the left front wheel mounting frame and the right front wheel mounting frame each comprise a steering knuckle (15), the steering knuckle (15) is rotatably arranged on the frame through a kingpin (16), the steering oil cylinder (12) is provided with two output ends and is rotatably connected to the cylinder barrels of the left floating oil cylinder (13) and the right floating oil cylinder (14) respectively, the cylinder rods of the left floating oil cylinder (13) and the right floating oil cylinder (14) are rotatably connected to the steering rocker arms (17) on the same side respectively; the middle parts of the inner cavities of the left floating oil cylinder (13) and the right floating oil cylinder (14) are each provided with a stop block (18), the stop block (18) divides the inner cavity of the cylinder barrel into a rod cavity (19), a rodless cavity (20) and a middle cavity (21), the rod cavity (19) and the rodless cavity (20) are each slidably provided with a sliding block (22) for moving towards each other under the action of the hydraulic oil, so as to lock the cylinder rod; the control valve set comprises a control valve one (23), a control valve two (24), a control valve three (25) and a control valve four (26), wherein the control valve one (23) and the control valve two (24) are used for adjusting the locking state of the cylinder rods of the left floating oil cylinder (13) and the right floating oil cylinder (14), and the control valve three (25) and the control valve four (26) are used for controlling the driving direction of the rear wheel driving mechanism; the oil circuit system further comprises: a first oil circuit (27) leading out from the hydraulic oil tank (1) and connected to the oil injection ports of the steering master pump one (4) and the steering master pump two (5) for providing the hydraulic oil for the steering master pump one (4) and the steering master pump two (5); A oil circuit (28) is led out from the oil outlet end of the steering main pump one (4), connected to the full hydraulic steering gear (8), steering oil cylinder (12) in turn, and finally flows back to the hydraulic oil tank (1), forming the main oil circuit circulation of steering control; B oil circuit (29) is led out from the oil outlet end of the steering main pump two (5), connected to the control valve one (23) and control valve two (24) respectively, providing power source for the hydraulic oil circuit of steering mode; C oil circuit (30) is set on the oil outlet end of control valve one (23), led out from control valve one (23), and provided with several oil inlet branches (31) connected with rod cavity (19) and rodless cavity (20), and each oil inlet branch (31) is provided with a hydraulic control check valve (32) for controlling the flow direction of hydraulic oil and locking the rod position of left floating oil cylinder (13) and right floating oil cylinder (14); D oil circuit (33) is led out from the middle cavity (21) and connected to the hydraulic oil tank (1), used for returning the hydraulic oil squeezed out from the cylinder of left floating oil cylinder (13) and right floating oil cylinder (14) to the hydraulic oil tank (1); Control oil circuit (34) is set on the oil outlet end of control valve two (24), led out from control valve two (24), and provided with several control oil branches (3) connected with the hydraulic control check valve (32) for controlling the opening and closing of hydraulic control check valve (32); Second oil circuit (35) is led out from the hydraulic oil tank (1) and connected to the oil inlet of rear wheel main pump one (6) and rear wheel main pump two (7) for providing hydraulic oil for rear wheel main pump one (6) and rear wheel main pump two (7); E oil circuit (36) is led out from the oil outlet end of rear wheel main pump one (6) and connected to control valve three (25) and left hydraulic motor (10) respectively, and finally flows back to the hydraulic oil tank (1), forming the oil circuit circulation of left rear wheel drive; F oil circuit (37) is led out from the oil outlet end of rear wheel main pump two (7) and connected to control valve four (26) and right hydraulic motor (11) respectively, and finally flows back to the hydraulic oil tank (1), forming the oil circuit circulation of right rear wheel drive.

2. The vehicle steering hydraulic control system according to claim 1, characterized by The first oil circuit (27) and the second oil circuit (35) are both provided with oil suction filter (38).

3. The vehicle steering hydraulic control system of claim 1, wherein The pressure relief oil circuit (39) is provided between the oil inlet branch (31) and D oil circuit (33), and the pressure relief valve (40) is provided on the pressure relief oil circuit (39).

4. A steering control method characterized by, The specific steps include the following steps: Step A: system initialization and default steering mode one setting After starting the vehicle, the system defaults to steering mode one; At this time, control valve one (23) and control valve two (24) are both in non-powered state, and the hydraulic control check valve (32) keeps its default closed state, which is one-way flow under this state, and can prevent the backflow of hydraulic oil; Start the steering main pump two (5), inject hydraulic oil into the rod cavity (19) and rodless cavity (20) of left floating oil cylinder (13) and right floating oil cylinder (14) through B oil circuit (29), C oil circuit (30) and oil inlet branch (31); In the mode, the slider (22) in the left floating oil cylinder (13) and the right floating oil cylinder (14) is close to each other under the action of hydraulic oil and pushes the cylinder rod to move to the middle until it is fixed by the stop block (18), the hydraulic oil squeezed out of the cylinder barrel of the left floating oil cylinder (13) and the right floating oil cylinder (14) returns to the hydraulic oil tank (1) through the D oil circuit (33), and the hydraulic oil in the rod cavity (19) and the rodless cavity (20) cannot flow backward through the oil inlet branch (31) in the closed state of the hydraulic control check valve (32), so that the locking and fixing of the cylinder rod position can be guaranteed, the left floating oil cylinder (13) and the right floating oil cylinder (14) are only used as connecting rods of the front wheel steering drive mechanism in this state, and the control valve three (25) and the control valve four (26) cannot be electrified in this state, the rotation speed of the left hydraulic motor (10) and the right hydraulic motor (11) is controlled by the oil door, and the vehicle speed is increased according to the depth of the oil door pedal; Step B: front wheel steering control in mode two Left steering: the driver rotates the steering wheel (9) to the left, the valve core of the full hydraulic steering gear (8) is rotated, and the pressure oil is pushed to the left cavity of the steering oil cylinder (12) through the A oil circuit (28), so that the cylinder rod of the steering oil cylinder (12) slides to the right, drives the left floating oil cylinder (13) and the right floating oil cylinder (14) to slide to the right, and then makes the left front wheel mounting frame, the right front wheel mounting frame and the front tire turn to the left side through the mechanical linkage relationship of the steering rocker arm (17), so as to realize left steering; Right steering: similarly, the driver rotates the steering wheel (9) to the right, the valve core of the full hydraulic steering gear (8) is rotated, and the pressure oil is pushed to the right cavity of the steering oil cylinder (12), so that the cylinder rod of the steering oil cylinder (12) slides to the left, and right steering is realized; Step C: entering steering mode two and preparing for spot steering Before the driver selects to enter steering mode two by operating the button, the controller needs to detect the vehicle speed and the steering wheel angle to determine whether the entering condition is met; if the condition is met, the controller controls the rotation speed of the left hydraulic motor (10) and the right hydraulic motor (11) according to the vehicle speed and the steering wheel angle to obtain a reasonable steering radius; the specific control logic is to calculate the tire angle according to the steering wheel (9) angle, and then to calculate the rear wheel speed ratio according to the angle to control the rotation speed of the left hydraulic motor (10) and the right hydraulic motor (11); After starting the vehicle, the driver selects to enter mode two by pressing the button, first judges whether the left hydraulic motor (10) and the right hydraulic motor (11) are less than the target value, if not, it still enters steering mode one; if it is satisfied, it is further judged whether the steering wheel (9) angle is less than the target value, if not, it still enters steering mode one; if it is satisfied, the control valve one (23) and the control valve two (24) are electrified, and the pressure oil is injected into the control port of the hydraulic control check valve (32) through the control oil circuit (34) and the control oil circuit (3), so that it loses the function of one-way flow, allows the hydraulic oil to flow backward to the hydraulic oil tank (1), at this time, the left floating oil cylinder (13) and the right floating oil cylinder (14) can change freely within a certain range, and prepare for spot steering; Step D: spot steering control in steering mode two Left turn in place: the driver rotates the steering wheel (9) to the left, the control valve three (25) is powered, the left hydraulic motor (10) is reversed, the control valve four (26) is not powered, the right hydraulic motor (11) is rotated forward; the left rear tire runs backward, the right rear tire runs forward, because the front wheels are in a floating state and have a traction angle, the front wheels automatically adjust the direction according to the speed difference of the rear wheels, and the left turn in place is realized; Right turn in place: the driver rotates the steering wheel (9) to the right, the control valve four (26) is powered, the right hydraulic motor (11) is reversed, the left hydraulic motor (10) is rotated forward, and the right turn in place is realized. Step E: mode switching and recovery When the driver needs to switch back to mode one, the control valve one (23) and the control valve two (24) are both powered off by operating the button, the hydraulic control check valve (32) restores the one-way flow function, the cylinder rods of the left floating oil cylinder (13) and the right floating oil cylinder (14) are locked and fixed again, and the system returns to the state of mode one.

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