A tractor front axle suspension system and method

Abstract

The application provides a tractor front axle suspension system and method. The tractor front axle suspension system is characterized in that a third electromagnetic reversing valve is connected with a first electromagnetic reversing valve and a second electromagnetic reversing valve, the first electromagnetic reversing valve and the second electromagnetic reversing valve are connected with a first throttle hole and a second throttle hole, the first throttle hole, the second throttle hole, a first pressure sensor and a second pressure sensor are connected with a first chamber of a left front axle support oil cylinder and a right front axle support oil cylinder, a first check valve and a second check valve are connected with the first throttle hole and the second throttle hole in parallel, one end of a pressure reducing valve and a second accumulator are connected with a pipeline between the second throttle hole and the right front axle support oil cylinder, a first accumulator is connected with a pipeline between the first throttle hole and the left front axle support oil cylinder, and the first pressure sensor, the second pressure sensor, the first electromagnetic reversing valve, the second electromagnetic reversing valve, the third electromagnetic reversing valve, a vehicle speed sensor and an angle sensor are connected with a vehicle control device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tractor front axle, and particularly relates to a tractor front axle suspension system and method. BACKGROUND

[0002] As an important agricultural machinery equipment, the working condition of the tractor is very complex, and different weights of machine tools are often connected in front and back, and work under uneven and complex terrain conditions. The traditional rigid front axle suspension system cannot effectively reduce the bumping and vibration of the front part of the vehicle, resulting in increased discomfort and fatigue of the driver and passengers.

[0003] In the prior art, the traditional technical solution usually adopts a rigid axle structure, in which the front axle is connected to the vehicle body through a suspension arm without the support of a suspension device or a shock absorber. The rigid axle system cannot effectively reduce the bumping and vibration of the front part of the vehicle, resulting in discomfort and fatigue of the driver and passengers on uneven terrain. Some tractor suspension systems use a combination of mechanical springs and shock absorbers to provide suspension function. However, these systems often cannot meet the needs of different road conditions. SUMMARY

[0004] The present application solves the technical problems of the prior art and provides a tractor front axle suspension system and method.

[0005] The technical scheme of the present application to solve the above technical problems is as follows: A tractor front axle suspension system, comprising: a first electromagnetic reversing valve, a second electromagnetic reversing valve, a third electromagnetic reversing valve, a pressure reducing valve, a first check valve, a second check valve, a first orifice, a second orifice, a first accumulator, a second accumulator, a front axle left side support oil cylinder, a front axle right side support oil cylinder, an oil inlet, an oil outlet, a first pressure sensor, a second pressure sensor, a vehicle control device, a vehicle speed sensor, an angle sensor, the first end of the third electromagnetic reversing valve is connected with the oil inlet through a pipeline, the second end of the third electromagnetic reversing valve is connected with the first electromagnetic reversing valve and the second electromagnetic reversing valve through a pipeline respectively, the first electromagnetic reversing valve and the second electromagnetic reversing valve are connected with the first orifice and the second orifice through a pipeline one by one, the first orifice is connected with the first chamber of the front axle left side support oil cylinder and the first chamber of the front axle right side support oil cylinder through a pipeline respectively, the second orifice is connected with the second chamber of the front axle left side support oil cylinder and the second chamber of the front axle right side support oil cylinder through a pipeline respectively, the first check valve and the second check valve are connected with the first orifice and the second orifice through a pipeline one by one, one end of the pressure reducing valve and the second accumulator are connected with the pipeline between the second orifice and the front axle right side support oil cylinder through a pipeline, the other end of the pressure reducing valve and the third end of the third electromagnetic reversing valve are connected with the oil outlet through a pipeline, the first accumulator is connected with the pipeline between the first orifice and the front axle left side support oil cylinder through a pipeline, the first pressure sensor is connected with the first chamber of the front axle left side support oil cylinder and the first chamber of the front axle right side support oil cylinder respectively, the second pressure sensor is connected with the second chamber of the front axle left side support oil cylinder and the second chamber of the front axle right side support oil cylinder respectively, the first pressure sensor, the second pressure sensor, the first electromagnetic reversing valve, the second electromagnetic reversing valve, the third electromagnetic reversing valve, the vehicle speed sensor and the angle sensor are connected with the vehicle control device.

[0006] The beneficial effects of the technical scheme of the present application are: the height and hardness of the suspension bridge can be passively adjusted according to the road conditions, so that the vehicle can better adapt to different road surfaces. The height and hardness of the suspension bridge are adjusted according to the load condition of the vehicle to achieve better load distribution. By adjusting the height of the suspension bridge, the load of the front and rear axles of the vehicle can be reasonably distributed, improving the balance and stability of the vehicle. The jolt and vibration of the front part of the vehicle are effectively reduced to meet the needs of different road conditions. The driving comfort is improved. The vehicle control device receives real-time data from the sensors, including vehicle speed, vehicle body posture, hydraulic system pressure changes caused by road conditions, etc., and then automatically adjusts the pressure and flow of the hydraulic system according to the preset algorithm and parameters, so as to realize the change of the height and hardness of the suspension bridge.

[0007] Further, the first end of the third electromagnetic reversing valve is connected with the oil inlet through a third throttling hole.

[0008] The beneficial effect of the above further technical solution is that the throttling hole is used to adjust the flow rate of the hydraulic oil, prevent the flow rate of the pressure oil from being too high, make the oil cylinder move smoothly, and improve the stability and reliability of the system.

[0009] Further, the oil inlet and the oil outlet are both connected with the oil tank through pipelines.

[0010] The beneficial effect of the above further technical solution is that the oil tank is used to provide hydraulic oil for the system.

[0011] Further, the vehicle control device is connected with a human-machine interface and an instrument.

[0012] The beneficial effect of the above further technical solution is that the human-machine interface is convenient for the user to input instructions to the system, and the instrument is convenient for the user to intuitively observe the working state of the system.

[0013] In addition, the present application also provides a tractor front axle suspension method based on the tractor front axle suspension system of any one of the above.

[0014] S1, the vehicle speed sensor obtains the tractor vehicle speed;

[0015] S2, the angle sensor obtains the tractor angle;

[0016] S3, the first pressure sensor respectively obtains the pressure of the first chamber of the front axle left side support oil cylinder and the pressure of the first chamber of the front axle right side support oil cylinder;

[0017] S4, the second pressure sensor respectively obtains the pressure of the second chamber of the front axle left side support oil cylinder and the pressure of the second chamber of the front axle right side support oil cylinder;

[0018] S5, the vehicle control device generates a control instruction according to the tractor vehicle speed, the tractor angle, the pressure of the first chamber of the front axle left side support oil cylinder, the pressure of the first chamber of the front axle right side support oil cylinder, the pressure of the second chamber of the front axle left side support oil cylinder, and the pressure of the second chamber of the front axle right side support oil cylinder;

[0019] S6, the first electromagnetic reversing valve, the second electromagnetic reversing valve, and the third electromagnetic reversing valve adjust the height and the pressure of the front axle left side support oil cylinder and the front axle right side support oil cylinder according to the control instruction, so that the front axle left side support oil cylinder and the front axle right side support oil cylinder are both kept in the middle position.

[0020] The beneficial effects of the technical scheme of the present application are: the height and hardness of the suspension bridge can be passively adjusted according to road conditions, so that the vehicle can better adapt to different road surfaces. The height and hardness of the suspension bridge are adjusted according to the load condition of the vehicle to achieve better load distribution. By adjusting the height of the suspension bridge, the load of the front and rear axles of the vehicle can be reasonably distributed, improving the balance and stability of the vehicle. The jolt and vibration of the front part of the vehicle are effectively reduced to meet the needs of different road conditions. The driving comfort is improved. The vehicle control device receives real-time data from sensors, including vehicle speed, vehicle body posture, hydraulic system pressure changes caused by road conditions, etc., and then automatically adjusts the pressure and flow of the hydraulic system according to the preset algorithm and parameters, thereby changing the height and hardness of the suspension bridge.

[0021] Further, step S1 includes:

[0022] S11, the vehicle control device is initialized;

[0023] S12, the vehicle control device determines whether the user inputs a switch calibration mode instruction;

[0024] S13, when the user does not input the switch calibration mode instruction, the vehicle control device switches to the automatic mode and executes steps S1 to S6.

[0025] The beneficial effects of the above further technical scheme are: if there is a specific user request, the system state will be changed to calibration mode after initialization; otherwise, the system state will generally switch to automatic mode at the end of initialization. When the system is powered on, some checks will be performed on the internal state. If there is a specific user request, the system state will be changed to calibration mode after initialization; otherwise, the system state will generally switch to automatic mode at the end of initialization.

[0026] Further, step S12 includes: when the user inputs the switch calibration mode instruction, the vehicle control device records the limit positions of the front axle left side support oil cylinder and the front axle right side support oil cylinder calibrated by the user, respectively.

[0027] The beneficial effects of the above further technical scheme are: if there is a specific user request, the system state will be changed to calibration mode after initialization. If a new axle has never been calibrated, the vehicle control device waits for the user to press the up (down) button 60 seconds after the system is powered on. The user should always hold the up (down) key until the front axle reaches the maximum (minimum) position of the left and right oil cylinders. When the user releases the up (down) button, the vehicle control device uses the current position as the maximum (minimum) position. The user can repeat the up and down movements multiple times, and each time the user completes the up and down (or up and down) operation, the recorded value will be overwritten.

[0028] Further, the vehicle control device determines whether the user inputs a manual mode switching instruction or a lock mode switching instruction at any of steps S1 to S6.

[0029] When the user inputs the manual mode switching instruction or the lock mode switching instruction, the vehicle control device determines whether the vehicle speed is less than a preset vehicle speed.

[0030] When the vehicle speed is less than the preset vehicle speed, the vehicle control device switches to the manual mode according to the manual mode switching instruction or switches to the lock mode according to the lock mode switching instruction.

[0031] The beneficial effect of the above further technical solution is that in the lock mode, the oil cylinder retracts to its minimum stroke, and the tractor head is lowered to the lowest, at this time, the height adjustment and suspension functions (pressure control) of the system are not available. In the manual mode, the system adjusts the front axle height within the minimum value and the maximum value according to the human-machine interface input signal (up / down), and when the tractor speed exceeds 3kph, the system state is switched to the automatic mode.

[0032] Further, when the vehicle speed is less than the preset value, the vehicle control device switches to the manual mode according to the manual mode switching instruction or switches to the lock mode according to the lock mode switching instruction.

[0033] In the manual mode or the lock mode, the vehicle control device determines whether the vehicle speed is greater than a preset vehicle speed.

[0034] When the vehicle speed is greater than the preset vehicle speed, the vehicle control device switches to the automatic mode.

[0035] The beneficial effect of the above further technical solution is that in the automatic mode, the front axle height and the oil cylinder pressure can be automatically adjusted according to the load attached to the tractor and the road condition, and the height adjustment and suspension control functions are available.

[0036] Further, step S5 includes: S51, the vehicle control device determines whether the front axle left side support oil cylinder and the front axle right side support oil cylinder are both in the middle position;

[0037] S52, when the front axle left side support oil cylinder or the front axle right side support oil cylinder is not in the middle position, the vehicle control device determines whether the time of not being in the middle position exceeds a preset time;

[0038] S53, when the time of not being in the middle position exceeds the preset time, the vehicle control device generates a control instruction according to the tractor speed, the tractor angle, the pressure of the first chamber of the front axle left side support oil cylinder, the pressure of the first chamber of the front axle right side support oil cylinder, the pressure of the second chamber of the front axle left side support oil cylinder, and the pressure of the second chamber of the front axle right side support oil cylinder.

[0039] The beneficial effects of the further technical scheme are that the vehicle control reads the angle sensor signal in real time, converts the angle sensor signal into the oil cylinder height percentage, when the oil cylinder position cannot be kept in the middle position due to the bumping and vibration of the tractor, when the position exceeds 5% and the time exceeds the set threshold, the vehicle control unit opens the corresponding electromagnetic valve to increase the pressure of the large cavity or small cavity of the oil cylinder, and then adjusts the stroke of the oil cylinder to keep in the middle position.

[0040] The advantages of the additional aspects of the application will be partially given in the following description, partially will become apparent from the following description, or will be understood by the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 The structure schematic view of the front axle suspension system provided by the embodiment of the application is shown.

[0042] Figure 2 The structure schematic view of the front axle suspension system provided by the embodiment of the application is shown.

[0043] Figure 3 The structure schematic view of the front axle suspension system provided by the embodiment of the application is shown.

[0044] Figure 4 The structure schematic view of the front axle suspension system provided by the embodiment of the application is shown.

[0045] Figure 5 The structure schematic view of the front axle suspension system provided by the embodiment of the application is shown.

[0046] BRIEF DESCRIPTION OF DRAWINGS: 1, main valve block; 21, first electromagnetic directional valve; 22, second electromagnetic directional valve; 3, third electromagnetic directional valve; 4, angle sensor; 5, pressure reducing valve; 61, first check valve; 62, second check valve; 71, first throttle hole; 72, second throttle hole; 8, third throttle hole; 9, first accumulator; 10, second accumulator; 111, front axle left side support oil cylinder; 112, front axle right side support oil cylinder; 12, first pressure sensor; 13, second pressure sensor; 14, vehicle control device; 15, vehicle speed sensor; 17, human-computer interface; 18, instrument. DETAILED DESCRIPTION

[0047] The principles and features of the application are described below in combination with the drawings, and the examples are only used to explain the application, and are not used to limit the scope of the application.

[0048] As Figure 1 and Figure 2As shown, the tractor front axle suspension system provided by the embodiment of the present application comprises a first electromagnetic reversing valve 21, a second electromagnetic reversing valve 22, a third electromagnetic reversing valve 3, a pressure reducing valve 5, a first check valve 61, a second check valve 62, a first throttling hole 71, a second throttling hole 72, a first accumulator 9, a second accumulator 10, a front axle left side support oil cylinder 111, a front axle right side support oil cylinder 112, an oil inlet, an oil outlet, a first pressure sensor 12, a second pressure sensor 13, a vehicle control device 14, a vehicle speed sensor 15, and an angle sensor 4. The first end of the third electromagnetic reversing valve 3 is connected with the oil inlet through a pipeline. The second end of the third electromagnetic reversing valve 3 is connected with the first electromagnetic reversing valve 21 and the second electromagnetic reversing valve 22 through pipelines respectively. The first electromagnetic reversing valve 21 and the second electromagnetic reversing valve 22 are connected with the first throttling hole 71 and the second throttling hole 72 through pipelines one by one. The first throttling hole 71 is connected with the first chamber of the front axle left side support oil cylinder 111 and the first chamber of the front axle right side support oil cylinder 112 through pipelines respectively. The second throttling hole 72 is connected with the second chamber of the front axle left side support oil cylinder 111 and the second chamber of the front axle right side support oil cylinder 112 through pipelines respectively. The first check valve 61 and the second check valve 62 are connected with the first throttling hole 71 and the second throttling hole 72 through pipelines one by one in parallel. One end of the pressure reducing valve 5 and the second accumulator 10 are connected with the pipeline between the second throttling hole 72 and the front axle right side support oil cylinder 112 through pipelines. The other end of the pressure reducing valve 5 and the third end of the third electromagnetic reversing valve 3 are connected with the oil outlet through a pipeline. The first accumulator 9 is connected with the pipeline between the first throttling hole 71 and the front axle left side support oil cylinder 111 through a pipeline. The first pressure sensor 12 is connected with the first chamber of the front axle left side support oil cylinder 111 and the first chamber of the front axle right side support oil cylinder 112 respectively. The second pressure sensor 13 is connected with the second chamber of the front axle left side support oil cylinder 111 and the second chamber of the front axle right side support oil cylinder 112 respectively. The first pressure sensor 12, the second pressure sensor 13, the first electromagnetic reversing valve 21, the second electromagnetic reversing valve 22, the third electromagnetic reversing valve 3, the vehicle speed sensor 15, and the angle sensor 4 are connected with the vehicle control device 14.

[0049] The beneficial effects of the technical scheme of the present application are: the height and hardness of the suspension bridge can be passively adjusted according to road conditions, so that the vehicle can better adapt to different road surfaces. The height and hardness of the suspension bridge are adjusted according to the load condition of the vehicle to achieve better load distribution. By adjusting the height of the suspension bridge, the load of the front and rear axles of the vehicle can be reasonably distributed, improving the balance and stability of the vehicle. Effectively reduce the bump and vibration of the front of the vehicle, meet the needs of different road conditions. Improve driving comfort. The vehicle control device receives real-time data from sensors, including vehicle speed, vehicle body posture, hydraulic system pressure changes caused by road conditions, etc., and then automatically adjusts the pressure and flow of the hydraulic system according to the preset algorithm and parameters, thereby changing the height and hardness of the suspension bridge.

[0050] wherein, Figure 1 P is the oil inlet, and T is the oil outlet. The first electromagnetic reversing valve, the second electromagnetic reversing valve, the third electromagnetic reversing valve, the pressure reducing valve, the first check valve, the second check valve, the first throttle hole, the second throttle hole, and the third throttle hole are all installed in the main valve block 1, Figure 1 The bottom dashed box in the figure is the main valve block 1, and the top dashed box is the front axle suspension mechanism.

[0051] Road adaptability: Different road conditions require different requirements for vehicle suspension systems. Through electronic hydraulic control, the front axle suspension system can passively adjust the height and hardness of the suspension bridge according to road conditions, so that the vehicle can better adapt to different road surfaces, including uneven terrain, bumpy roads, and uneven ground.

[0052] Driving comfort: Traditional rigid bridge suspension systems cannot effectively reduce the bump and vibration from the road, causing discomfort and fatigue for drivers and passengers. The electronic hydraulic control front axle suspension system can significantly improve driving comfort by adjusting the hardness and damping effect of the suspension bridge (front axle), reducing the impact of bump and vibration on vehicle occupants.

[0053] Load distribution: The electronic hydraulic control front axle suspension system can also adjust the height and hardness of the suspension bridge according to the load condition of the vehicle to achieve better load distribution. By adjusting the height of the suspension bridge, the load of the front and rear axles of the vehicle can be reasonably distributed, improving the balance and stability of the vehicle.

[0054] Automatic control: The system can achieve automatic suspension control through electronic control equipment (VCU, vehicle control unit). The VCU receives real-time data from sensors, including vehicle speed, vehicle body posture, hydraulic system pressure changes caused by road conditions, etc., and then automatically adjusts the pressure and flow of the hydraulic system according to the preset algorithm and parameters, thereby changing the height and hardness of the suspension bridge.

[0055] In summary, the electronically controlled hydraulic front axle suspension system can solve the technical problems of road adaptability, driving comfort, driving stability, load distribution and automatic control.

[0056] The present invention consists of a mechanical hydraulic electronic system that will keep the front axle height in the middle position, i.e. the front axle support cylinder in the range of 50% (+ / - 5%) as long as the actual front axle load of the tractor is within a given range. If the front axle load changes, the system will adjust the cylinder pressure accordingly. If driving at the maximum speed of the vehicle (tractor), the system allows the cylinder of the front axle to swing between 0% and 100% of the stroke without the intervention of the control system.

[0057] Height adjustment

[0058] To ensure the above requirements, the system should automatically adjust the height after the front axle load changes.

[0059] Pressure control

[0060] After the hydraulic cylinder control reaches the required stroke position of 50% (+ / - 5%), the control system will increase or decrease the large cavity pressure of the cylinder to keep the natural frequency of the vehicle within the required range.

[0061] Principle of the electronically controlled hydraulic system (tractor front axle suspension system)

[0062] Increase large cavity pressure (if the cylinder pressure is greater than the front axle load, the guide cylinder extends downward)

[0063] The second electromagnetic directional valve 22 and the third electromagnetic directional valve 3 must be fully energized at the same time.

[0064] The third electromagnetic directional valve 3 (3 / 2 directional valve) is energized to open, and the hydraulic oil source enters from the P port. The second electromagnetic directional valve 22 (2 / 2 directional valve) is energized to open to increase the pressure of the hydraulic oil on the large cavity (second chamber) side of the cylinder. For this flow direction, the second check valve 62 (check valve) is open and bypasses the second orifice 72. The flow is limited by the third orifice 8 in this case, controlling the flow to an ideal level.

[0065] Decrease large cavity pressure (cylinder retracts upward)

[0066] Only the second electromagnetic directional valve 22 needs to be energized.

[0067] The third electromagnetic directional valve 3 is always open to the tank T (oil outlet), and the oil (hydraulic oil) can be immediately released to the tank. In this flow direction, the oil from the piston side (first chamber, i.e. the side of the piston rod) is blocked by the second check valve 62 and must pass through the second orifice 72. The restriction is to control the pressure drop rate to a reasonable value so that the front axle suspension system does not suddenly drop.

[0068] Increase small chamber pressure (cylinder retracting upwards)

[0069] The first electromagnetic directional valve 21 and the third electromagnetic directional valve 3 must be energized at the same time.

[0070] The third electromagnetic directional valve 3 (3 / 2 directional valve) is energized to open, and the hydraulic oil source enters from the P port (oil inlet), and the first electromagnetic directional valve 21 (2 / 2 directional valve) is energized to open to increase the pressure of the hydraulic oil on the small chamber side (first chamber, piston rod side) of the oil cylinder. For this flow direction, the first check valve 61 (check valve) is opened and bypasses the first throttle hole 71.

[0071] Decrease chamber pressure (cylinder extending downwards)

[0072] Only the first electromagnetic directional valve 21 needs to be energized.

[0073] The third electromagnetic directional valve 3 is always open to the tank, and the oil (hydraulic oil) can be immediately released to the tank. In this flow direction, the oil from the piston side (second chamber) is blocked by the check valve (first check valve 61) and must pass through the first throttle hole 71. The restriction is to control the pressure drop speed to a reasonable value so that the front axle suspension system does not suddenly rise.

[0074] Impact load on the piston side (first chamber, piston rod side) (cylinder retracting upwards)

[0075] During the operation of the system in automatic mode, the vehicle (tractor) travels at a given vehicle speed, and if it is excited by the road, it causes a high pressure peak, which requires the pressure relief valve (pressure relief valve 5) to open and release the large chamber (second chamber) pressure. Prevent damage to the entire hydraulic system (oil cylinder, accumulator, valve and structure).

[0076] After the safety valve (pressure relief valve) is opened in automatic mode, the cylinder position may deviate from the neutral position (50% + / - 5%), and the control system needs to readjust the position to its target value by increasing the pressure on the piston side (first chamber, piston rod side).

[0077] As shown in Figure 1 Further, the first end of the third electromagnetic directional valve 3 is connected with the oil inlet through the third throttle hole 8.

[0078] The beneficial effects of the above further technical solutions are that the throttle hole is used to adjust the flow rate of the hydraulic oil, prevent the flow rate of the pressure oil from being too high, make the oil cylinder move smoothly, and improve the stability and reliability of the system.

[0079] Further, the oil inlet and the oil outlet are both connected with the tank through pipelines.

[0080] The beneficial effect of the further technical scheme is that the oil tank is used for providing hydraulic oil for the system.

[0081] As shown in Figure 2 Further, the whole vehicle control device 14 is connected with a human-machine interface 17 and an instrument 18.

[0082] The beneficial effect of the further technical scheme is that the human-machine interface is convenient for a user to input instructions to the system, and the instrument is convenient for the user to intuitively observe the working state of the system.

[0083] As shown in Figure 2 The human-machine interface can be provided with buttons "up", "down", "automatic", and "lock".

[0084] As shown in Figure 3 In addition, the present application also provides a tractor front axle suspension method based on the tractor front axle suspension system of any one of the above, and the tractor front axle suspension method comprises the following steps:

[0085] S1, a vehicle speed sensor acquires the vehicle speed of the tractor;

[0086] S2, an angle sensor acquires the angle of the tractor;

[0087] S3, a first pressure sensor respectively acquires the pressure of the first chamber of the left side support oil cylinder of the front axle and the pressure of the first chamber of the right side support oil cylinder of the front axle;

[0088] S4, a second pressure sensor respectively acquires the pressure of the second chamber of the left side support oil cylinder of the front axle and the pressure of the second chamber of the right side support oil cylinder of the front axle;

[0089] S5, a whole vehicle control device generates a control instruction according to the vehicle speed of the tractor, the angle of the tractor, the pressure of the first chamber of the left side support oil cylinder of the front axle, the pressure of the first chamber of the right side support oil cylinder of the front axle, the pressure of the second chamber of the left side support oil cylinder of the front axle, and the pressure of the second chamber of the right side support oil cylinder of the front axle;

[0090] S6, a first electromagnetic directional valve, a second electromagnetic directional valve, and a third electromagnetic directional valve adjust the height and pressure of the left side support oil cylinder of the front axle and the right side support oil cylinder of the front axle according to the control instruction, so that the left side support oil cylinder of the front axle and the right side support oil cylinder of the front axle are both kept in the middle position.

[0091] The beneficial effects of the technical scheme of the present application are: the height and hardness of the suspension bridge can be passively adjusted according to road conditions, so that the vehicle can better adapt to different road surfaces. The height and hardness of the suspension bridge are adjusted according to the load condition of the vehicle to achieve better load distribution. By adjusting the height of the suspension bridge, the load of the front and rear axles of the vehicle can be reasonably distributed, improving the balance and stability of the vehicle. The jolt and vibration of the front part of the vehicle are effectively reduced to meet the needs of different road conditions. The driving comfort is improved. The vehicle control device receives real-time data from the sensors, including vehicle speed, vehicle body posture, hydraulic system pressure changes caused by road conditions, and then automatically adjusts the pressure and flow of the hydraulic system according to the preset algorithm and parameters, so as to realize the change of the height and hardness of the suspension bridge.

[0092] As shown in Figure 4 , power on, 1, initialization; 2, normally start the engine and enter the automatic mode; 3, the manual mode switch is pressed and the vehicle speed is less than 3kph, enter the manual mode; 4, the automatic mode switch is pressed or the vehicle speed is greater than 3kph, enter the automatic mode; 5, the lock mode switch is pressed and the vehicle speed is less than 3kph, enter the lock mode; 6, the automatic mode switch is pressed or the vehicle speed is greater than 3kph, enter the automatic mode; step 1 includes: press the automatic mode switch and the up switch at the same time to start the engine and enter the calibration mode (calibration mode).

[0093] As shown in Figure 5 , closed-loop control method: the signals of the angle sensor (target position) and the angle sensor (actual position) are transmitted to the control unit (vehicle control device), and the angle sensor (actual position) and the control unit constitute a closed-loop control; the closed-loop control output electromagnetic valve control current is transmitted to the input end of the vehicle control loop, wherein the vehicle control loop includes a control valve (which can be an electromagnetic reversing valve), a hydraulic circuit, and an execution element (oil cylinder, accumulator, etc.), and the output end signal of the vehicle control loop is transmitted to the closed-loop control input position. The disturbance to the execution element is road unevenness, load change, acceleration / deceleration, uphill / downhill, etc.; the disturbance to the control valve is the change of the hydraulic system pressure.

[0094] Further, step S1 includes:

[0095] S11, the vehicle control device is initialized;

[0096] S12, the vehicle control device determines whether the user inputs a calibration mode switching instruction;

[0097] S13, when the user does not input the calibration mode switching instruction, the vehicle control device switches to the automatic mode and executes steps S1 to S6.

[0098] The beneficial effect of the further technical scheme is that if there is a specific user request, the system state will be changed to calibration mode after initialization, otherwise, the system state will generally switch to automatic mode at the end of initialization. When the system is powered on, some checks will be performed on the internal state. If there is a specific user request, the system state will be changed to calibration mode after initialization; otherwise, the system state will generally switch to automatic mode at the end of initialization.

[0099] Further, step S12 comprises: when the user inputs the switching calibration mode instruction, the vehicle control device records the limit positions of the front axle left side support oil cylinder and the front axle right side support oil cylinder calibrated by the user respectively.

[0100] The beneficial effect of the further technical scheme is that if there is a specific user request, the system state will be changed to calibration mode after initialization. If a new axle has never been calibrated, after the system is powered on for 60 seconds, the vehicle control device waits for the user to press the up (down) button. The user should always hold the up (down) key until the front axle reaches the maximum (minimum) position of the left and right oil cylinders. When the user releases the up (down) button, the vehicle control device uses the current position as the maximum (minimum) position. The user can repeat the up and down movement multiple times, and each time the user completes the up and down (or up and down) operation, the recorded value will be overwritten.

[0101] Further, at any of steps S1 to S6, the vehicle control device judges whether the user inputs the switching manual mode instruction or inputs the switching lock mode instruction;

[0102] When the user inputs the switching manual mode instruction or inputs the switching lock mode instruction, the vehicle control device judges whether the vehicle speed is less than a preset vehicle speed;

[0103] When the vehicle speed is less than the preset vehicle speed, the vehicle control device switches to the manual mode according to the switching manual mode instruction or switches to the lock mode according to the switching lock mode instruction.

[0104] The beneficial effect of the further technical scheme is that in the lock mode, the oil cylinder retracts to its minimum stroke, and the tractor head is lowered to the lowest, at which time the height adjustment and suspension function (pressure control) of the system are not available. In the manual mode, the system adjusts the front axle height within the minimum and maximum values according to the human-machine interface input signal (up / down), and when the tractor vehicle speed exceeds 3kph, the system state will switch to the automatic mode.

[0105] Further, the step of switching to the manual mode according to the switching manual mode instruction or switching to the lock mode according to the switching lock mode instruction when the vehicle speed is less than the preset value comprises:

[0106] In the manual mode or the lock mode, the vehicle control device judges whether the vehicle speed is greater than a preset vehicle speed;

[0107] When the vehicle speed is greater than the preset vehicle speed, the vehicle control device switches to the automatic mode.

[0108] The beneficial effect of the further technical solution is that in the automatic mode, the front axle height and the oil cylinder pressure can be automatically adjusted according to the load connected to the tractor and the road state, and the height adjustment and suspension control functions are provided.

[0109] Further, the step S5 comprises: S51, the vehicle control device judges whether the front axle left side support oil cylinder and the front axle right side support oil cylinder are both located at the middle position;

[0110] S52, when the front axle left side support oil cylinder or the front axle right side support oil cylinder is not located at the middle position, the vehicle control device judges whether the time of not being located at the middle position exceeds a preset time;

[0111] S53, when the time of not being located at the middle position exceeds the preset time, the vehicle control device generates a control instruction according to the tractor speed, the tractor angle, the pressure of the first chamber of the front axle left side support oil cylinder, the pressure of the first chamber of the front axle right side support oil cylinder, the pressure of the second chamber of the front axle left side support oil cylinder, and the pressure of the second chamber of the front axle right side support oil cylinder.

[0112] The beneficial effect of the further technical solution is that the vehicle control reads the angle sensor signal in real time, converts it into the oil cylinder height percentage, when the oil cylinder position cannot be kept at the middle position due to bumps and vibrations of the tractor, when the position exceeds 5% and the time exceeds the set threshold, the vehicle control unit increases the pressure of the large chamber or the small chamber of the oil cylinder by opening the corresponding electromagnetic valve, and then adjusts the stroke of the oil cylinder to keep it at the middle position.

[0113] Initialization:

[0114] When the system is powered on, some checks will be performed on the internal state. If there is a specific user request, the system state will be changed to calibration mode after initialization; otherwise, at the end of initialization, the system state will usually switch to the automatic mode.

[0115] Manual mode:

[0116] In the manual mode, the system adjusts the front axle height within the minimum value and the maximum value according to the HMI (Human Machine Interface) input signal (up / down), and when the tractor speed exceeds 3kph, the system state will switch to the automatic mode.

[0117] Calibration mode:

[0118] If a new axle has never been calibrated, after the system is powered on for 60 seconds, the vehicle control device waits for the user to press the up (down) button. The user should hold the up (down) key until the front axle reaches the maximum (minimum) position of the left and right cylinders (extreme position). When the user releases the up (down) button, the vehicle control device uses the current position as the maximum (minimum) position. The user can repeat the up and down movement multiple times, and each time the user completes the up and down (or up and down) operation, the recorded value is overwritten.

[0119] Lock mode:

[0120] In lock mode, the cylinders retract to their minimum stroke, and the tractor head is lowered to the lowest position, at which point the system's height adjustment and levitation functions (pressure control for levitation) are not available.

[0121] Automatic mode:

[0122] In automatic mode, the system can automatically adjust the front axle height and cylinder pressure based on the load attached to the tractor and the road conditions, with height adjustment and levitation control functions.

[0123] Height adjustment method:

[0124] The vehicle control reads the angle sensor signal in real time and converts it to the cylinder (front axle left and right support cylinders) height percentage. When the tractor's position cannot be maintained in the middle due to bumps and vibrations, and the position exceeds 5% and the time exceeds the set threshold (preset time), the vehicle control device increases the pressure in the large or small cavity of the corresponding cylinder by opening the corresponding solenoid valve, thereby adjusting the cylinder stroke to maintain it in the middle.

[0125] Levitation control method:

[0126] The natural frequency of the tractor refers to the inherent frequency of the front axle in a free vibration state. Generally, the natural frequency of the tractor front axle should be between 2Hz and 4Hz. This range is considered relatively suitable empirically, as it can provide appropriate suspension stiffness and vibration suppression capability while maintaining sufficient comfort and stability.

[0127] If the natural frequency is too low (below 2Hz), the tractor may exhibit excessively soft suspension characteristics, resulting in excessive vertical vibration and instability. This can negatively impact the driver's comfort and maneuverability.

[0128] Conversely, if the natural frequency is too high (above 4Hz), the tractor may become too rigid and unable to effectively absorb ground irregularities and impact forces, resulting in greater vibration transmission to the vehicle and the driver.

[0129] The size of the front axle load will affect the stiffness and vibration characteristics of the tractor, and thus affect the natural frequency of the tractor. A larger front axle load will increase the stiffness of the tractor, making the free vibration frequency of the front axle higher. Conversely, a smaller front axle load will reduce the stiffness of the tractor, making the free vibration frequency of the front axle lower.

[0130] If the natural frequency is too high, it indicates that the front axle is too stiff, and the stiffness of the oil cylinder needs to be reduced.

[0131] Reducing the stiffness of the oil cylinder can be achieved by reducing the small cavity pressure supporting the oil cylinder.

[0132] Increasing the stiffness of the oil cylinder can be achieved by increasing the small cavity pressure supporting the oil cylinder.

[0133] Improve driving comfort: The suspension control system (front axle suspension system) can effectively reduce the vibration and impact force of the tractor front axle, reduce the jolt of the driver on uneven road surface, and provide a more stable and comfortable driving experience.

[0134] Improve traction performance: The suspension control system can automatically adjust the suspension stiffness of the front axle according to the road conditions, so that the front wheels maintain better ground contact and provide more stable traction, thereby improving the traction performance and driving stability of the tractor.

[0135] Reduce driver fatigue: The optimized adjustment of the suspension control system (front axle suspension system) can reduce the fatigue caused by jolt and vibration when the driver drives for a long time, improve the comfort and work efficiency of the driver.

[0136] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A tractor front axle suspension system, characterized by, The system comprises a first electromagnetic reversing valve, a second electromagnetic reversing valve, a third electromagnetic reversing valve, a pressure reducing valve, a first check valve, a second check valve, a first orifice, a second orifice, a first accumulator, a second accumulator, a front axle left side support oil cylinder, a front axle right side support oil cylinder, an oil inlet, an oil outlet, a first pressure sensor, a second pressure sensor, a vehicle control device, a vehicle speed sensor, and an angle sensor. The first end of the third electromagnetic reversing valve is connected to the oil inlet through a third orifice.

2. A tractor front axle suspension system as set forth in claim 1, wherein, The oil inlet and the oil outlet are both connected to an oil tank through pipelines.

3. The tractor front axle suspension system of claim 1, wherein, The vehicle control device is connected to a human-machine interface and an instrument.

4. The tractor front axle suspension system of claim 1, wherein, The tractor front axle suspension system and method according to any one of claims 1 to 4 comprises:

5. A method of suspending a tractor front axle, characterized by S1, the vehicle speed sensor acquires the speed of the tractor under different road conditions and different load conditions; S2, the angle sensor acquires the angle of the tractor; S3, the first pressure sensor acquires the pressure of the first chamber of the front axle left side support oil cylinder and the pressure of the first chamber of the front axle right side support oil cylinder, respectively; S4, the second pressure sensor acquires the pressure of the second chamber of the front axle left side support oil cylinder and the pressure of the second chamber of the front axle right side support oil cylinder, respectively; ​ S5, the whole vehicle control device generates a control instruction according to the tractor speed, the tractor angle, the pressure of the first chamber of the front axle left support oil cylinder, the pressure of the first chamber of the front axle right support oil cylinder, the pressure of the second chamber of the front axle left support oil cylinder, and the pressure of the second chamber of the front axle right support oil cylinder; S6, the first electromagnetic directional control valve, the second electromagnetic directional control valve, and the third electromagnetic directional control valve adjust the height and pressure of the front axle left support oil cylinder and the front axle right support oil cylinder according to the control instruction, so that the front axle left support oil cylinder and the front axle right support oil cylinder are both kept in the middle position.

6. The tractor front axle suspension method according to claim 5, characterized in that, Before step S1, the following steps are included: S11, the whole vehicle control device initializes; S12, the whole vehicle control device judges whether the user inputs a switch calibration mode instruction; S13, when the user does not input the switch calibration mode instruction, the whole vehicle control device switches to the automatic mode and executes steps S1 to S6.

7. A method of suspending a front axle of a tractor as defined in claim 6, wherein, Step S12 includes: when the user inputs the switch calibration mode instruction, the whole vehicle control device records the limit positions of the front axle left support oil cylinder and the front axle right support oil cylinder calibrated by the user respectively.

8. The method of claim 5, wherein, At any step of steps S1 to S6, the whole vehicle control device judges whether the user inputs a switch manual mode instruction or a switch locking mode instruction; When the user inputs the switch manual mode instruction or the switch locking mode instruction, the whole vehicle control device judges whether the vehicle speed is less than a preset vehicle speed; When the vehicle speed is less than the preset vehicle speed, the whole vehicle control device switches to the manual mode according to the switch manual mode instruction or switches to the locking mode according to the switch locking mode instruction.

9. The tractor front axle suspension method according to claim 8, characterized in that, When the vehicle speed is less than the preset value, the step of the whole vehicle control device switching to the manual mode according to the switch manual mode instruction or switching to the locking mode according to the switch locking mode instruction includes: In the manual mode or the locking mode, the whole vehicle control device judges whether the vehicle speed is greater than a preset vehicle speed; When the vehicle speed is greater than the preset vehicle speed, the whole vehicle control device switches to the automatic mode.

10. The method of claim 5, wherein, Step S5 includes: S51, the whole vehicle control device judges whether the front axle left support oil cylinder and the front axle right support oil cylinder are both in the middle position; S52, when the front axle left support oil cylinder or the front axle right support oil cylinder is not in the middle position, the whole vehicle control device judges whether the time of not being in the middle position exceeds a preset time; S53, when the time of not being in the middle position exceeds the preset time, the whole vehicle control device generates a control instruction according to the tractor speed, the tractor angle, the pressure of the first chamber of the front axle left support oil cylinder, the pressure of the first chamber of the front axle right support oil cylinder, the pressure of the second chamber of the front axle left support oil cylinder, and the pressure of the second chamber of the front axle right support oil cylinder.

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