Tractor suspension front axle control method and system

Abstract

The invention provides a tractor suspension front axle control method and system. A tractor suspension front axle control method comprises the steps that in an automatic mode, the actual position of a suspension front axle, the ring side pressure of an oil cylinder and the piston side pressure of the oil cylinder are obtained; according to the ring side pressure of the oil cylinder and the piston side pressure of the oil cylinder, the load of the suspension front axle is obtained; obtaining a target position of an automatic mode according to the load of the suspension front axle and the ring side pressure of the oil cylinder; according to the actual position of the suspension front axle, the ring side pressure of the oil cylinder, the piston side pressure of the oil cylinder, the target position of the automatic mode and the preset pressure range of the oil cylinder, an adjusting strategy of the automatic mode is determined; and adjusting the suspension front axle according to the adjustment strategy of the automatic mode. In the locking mode, the pressure of the piston side is relieved, and the position of the front axle is kept unchanged; the position of the front axle is manually adjusted in the manual mode; and logic switching among the three modes is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of floating front axles, and in particular to a control method and system for a floating front axle of a tractor. Background Art

[0002] Tractors are widely used in agriculture and engineering. Traditional front axle designs are mostly rigid connections. Although simple in structure, when driving on uneven roads, vibrations and impacts will directly affect driving comfort and operation stability. With technological progress, floating front axle technology has gradually been introduced to improve the driving smoothness and controllability of tractors. The floating front axle realizes the suspension function through a hydraulic or pneumatic system, which can effectively absorb ground impacts and vibrations, significantly improve driving smoothness and comfort, and reduce the fatigue of the driver. This is particularly important for drivers working for long hours and can improve work efficiency and operation quality.

[0003] At the same time, the floating front axle can effectively reduce the direct transmission of ground impacts to the chassis, thereby reducing the vibration and stress of the chassis and extending the service life of the chassis. This is particularly important for high-power tractors because of their high operating intensity and higher requirements for the durability of the chassis. The floating front axle can better adapt to complex road conditions and match different working conditions, thereby improving the traction and operation efficiency of the tractor. In addition, the floating front axle can further improve the stability and controllability of the vehicle by optimizing the parameters of the suspension system.

[0004] In the existing front axle suspension system, one end of an oil cylinder is connected to a bracket of the vehicle body, the other end of the oil cylinder is connected to a rocker arm, and the front axle is arranged on the rocker arm. The oil cylinder is controlled to be in the middle position (i.e., the elongation is about 50%) to absorb vibrations, thereby reducing the bumps and vibrations at the front of the vehicle. However, due to the complex working terrain of the tractor, when the terrain changes, the vibration frequency and amplitude of the front axle change accordingly, and the resistance of the oil pressure cylinder cannot be adjusted adaptively with the vibration amplitude of the front axle, resulting in variable vibration frequency and amplitude of the front axle and unable to effectively improve the comfort of the driver and passengers. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a control method and system for a floating front axle of a tractor in view of the deficiencies of the prior art.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: A control method for a floating front axle of a tractor, comprising: in the automatic mode, obtaining the actual position of the floating front axle, the annular side pressure of the oil cylinder, and the piston side pressure of the oil cylinder; obtaining the load of the floating front axle according to the annular side pressure and the piston side pressure of the oil cylinder; obtaining the target position of the automatic mode according to the load of the floating front axle and the annular side pressure of the oil cylinder; determining the adjustment strategy of the automatic mode according to the actual position of the floating front axle, the annular side pressure of the oil cylinder, the piston side pressure of the oil cylinder, the target position of the automatic mode, and the preset pressure range of the oil cylinder; and adjusting the floating front axle according to the adjustment strategy of the automatic mode.

[0007] The beneficial effect of adopting the technical solution of the present invention is that the load of the floating front axle can be calculated through the annular side pressure and the piston side pressure, the target position is calculated through the obtained load and the actual annular side pressure, and when the position or pressure exceeds the target range and lasts for a certain period of time, the position / pressure is adjusted back to the target value. The position of the floating front axle is maintained at the target position in the automatic mode by position adjustment and pressure adjustment, and at the same time, the annular side is adjusted to a pressure value with a certain spring stiffness coefficient. It enables the driver to obtain a better shock absorption effect and a more comfortable driving experience.

[0008] Further, the step of determining the adjustment strategy of the automatic mode according to the actual position of the floating front axle, the annular side pressure of the oil cylinder, the piston side pressure of the oil cylinder, the target position of the automatic mode, and the preset pressure range of the oil cylinder includes: when the actual position of the floating front axle exceeds the target position of the automatic mode and lasts for the first preset time, adjusting the actual position of the floating front axle back to the target position of the automatic mode; when the actual pressure of the oil cylinder exceeds the preset pressure range of the oil cylinder and lasts for the second preset time, adjusting the actual pressure of the oil cylinder back to the preset pressure range of the oil cylinder.

[0009] The beneficial effect of adopting the above further technical solution is that the load of the floating front axle can be calculated through the annular side pressure and the piston side pressure, the target position is calculated through the obtained load and the actual annular side pressure, and when the position or pressure exceeds the target range and lasts for a certain period of time, the position / pressure is adjusted back to the target value. The position of the floating front axle is maintained at the target position in the automatic mode.

[0010] Further, the step of adjusting the actual pressure of the oil cylinder back to the preset pressure range of the oil cylinder when the actual pressure of the oil cylinder exceeds the preset pressure range of the oil cylinder and lasts for the second preset time includes: when the actual annular side pressure of the oil cylinder exceeds the preset annular side pressure range of the oil cylinder and lasts for the second preset time, adjusting the actual annular side pressure of the oil cylinder back to the first preset annular side pressure range of the oil cylinder.

[0011] The beneficial effects of adopting the above further technical solution are as follows: The load of the suspension front axle can be calculated through the ring side pressure and the piston side pressure. The target position is calculated based on the calculated load and the actual ring side pressure. After the position or pressure exceeds the target range and lasts for a period of time, the position / pressure is adjusted back to the target value. The ring side is adjusted to a pressure value with a certain spring stiffness coefficient.

[0012] Further, the target position of the automatic mode is adjacent to 50% of the total elongation of the oil cylinder, and the preset pressure range of the oil cylinder is the pressure range with a preset spring stiffness coefficient on the ring side of the oil cylinder.

[0013] The beneficial effects of adopting the above further technical solution are as follows: By position adjustment and pressure adjustment, the position of the suspension front axle is maintained at about 50%, and at the same time, the ring side is adjusted to a pressure value with a certain spring stiffness coefficient.

[0014] Further, the step of adjusting the suspension front axle according to the adjustment strategy of the automatic mode includes: first adjusting the actual position of the suspension front axle; when the actual position of the suspension front axle is adjacent to the target position of the automatic mode, adjusting the actual pressure of the oil cylinder.

[0015] The beneficial effects of adopting the above further technical solution are as follows: During the control adjustment in the automatic mode, the position and the ring side pressure of the suspension front axle are adjusted simultaneously. First, position control is performed, and then ring side pressure control is performed. In order to avoid repeated control, the ring side pressure control is advanced before the position reaches 50%. The change of the ring side pressure is controlled by the on / off of three solenoid valves.

[0016] Further, according to the range where the actual vehicle speed is located or by receiving a button command, the target mode is determined; according to the target mode and the current mode, the mode switching strategy is determined; according to the mode switching strategy, the current mode is switched to the target mode.

[0017] The beneficial effects of adopting the above further technical solution are as follows: According to the actual vehicle speed and the button command, the switching between modes is adaptively adjusted to ensure the stability of the suspension front axle control system of the tractor.

[0018] Further, the step of determining the mode switching strategy according to the target mode and the current mode includes: in the manual mode, when the vehicle speed is greater than the first preset speed, the manual mode is switched to the automatic mode; in the locked mode, when the vehicle speed is greater than the second preset speed, the locked mode is switched to the automatic mode; when the vehicle speed is not greater than the third preset speed, the automatic mode is switched to the locked mode.

[0019] The beneficial effects of adopting the above further technical solutions are as follows: In the manual mode, when the vehicle speed is greater than the first preset speed, to ensure the shock absorption effect of the floating front axle of the tractor, the tractor floating front axle control system automatically switches from the manual mode to the automatic mode, and when the vehicle stops, it will not return to the manual mode and the front axle will not be adjusted further; in the locking mode, when the vehicle speed is greater than the second preset speed, the tractor floating front axle control system switches from the locking mode to the automatic mode, and when the vehicle speed drops to the third preset speed, the tractor floating front axle control system returns to the locking mode.

[0020] Further, the step of determining the mode switching strategy according to the target mode and the current mode further includes: in the manual mode, switching the manual mode to the automatic mode or the locking mode according to the button instruction; in the automatic mode, switching the automatic mode to the manual mode or the locking mode according to the button instruction; in the locking mode, switching the locking mode to the automatic mode according to the button instruction.

[0021] The beneficial effects of adopting the above further technical solutions are as follows: To ensure the stability of the tractor floating front axle control system, logical restrictions are also imposed on the mode switching. In the manual mode, it can be switched to the automatic mode and the locking mode through the button. In the automatic mode, it can be switched to the manual mode and the locking mode through the button. In the locking mode, it can only be switched to the automatic mode through the button and cannot enter the manual mode.

[0022] Further, when switching to the locking mode, release the piston side pressure of the oil cylinder so that the oil cylinder contracts to 0% of the total elongation of the oil cylinder; when the piston side pressure of the oil cylinder drops to 0 bar and lasts for the third preset time, supply oil to the ring side of the oil cylinder; when the ring side pressure of the oil cylinder is greater than the second preset ring side pressure of the oil cylinder, stop supplying oil to the ring side of the oil cylinder, and the locking mode combination is completed; after the key is powered off, store the sub-state of the locking mode in the controller, and read the previous sub-state of the locking mode after powering on again; if the previous state was in the locking mode combination state or during the combination process, then automatically enter the locking mode after the engine is started this time; in the manual mode, when the actual telescopic position of the oil cylinder is within the range from the first preset position to the second preset position, supply oil to the piston side of the oil cylinder or drain the piston side of the oil cylinder according to the up button instruction or the down button instruction; in the manual mode, when the actual telescopic position of the oil cylinder exceeds the range from the first preset position to the second preset position and lasts for the fourth preset time, close the piston side of the oil cylinder and close the ring side of the oil cylinder.

[0023] The beneficial effects of adopting the above further technical solutions are as follows: The locking mode mainly fixes the position of the floating front axle at 0%, making the front axle become a rigid front axle to adapt to more required working conditions. The manual mode is mainly for the driver to connect the front-mounted implement and adjust the position of the front axle.

[0024] In addition, the present invention also provides a suspension front axle control system for a tractor, which is used to implement the tractor suspension front axle control method described in any one of the above. The tractor suspension front axle control system includes: a pair of double-acting cylinders, a pair of piston-side accumulators, an annular-side accumulator, a first on-off solenoid valve, a second on-off solenoid valve, a third on-off solenoid valve, an annular-side pressure sensor, a piston-side pressure sensor, a position sensor, a vehicle speed sensor, a touch screen, and a controller. The first on-off solenoid valve is respectively connected to the second on-off solenoid valve and the third on-off solenoid valve through pipelines. The second on-off solenoid valve is connected to the annular sides of a pair of the double-acting cylinders through a pipeline. The third on-off solenoid valve is connected to the piston sides of a pair of the double-acting cylinders through a pipeline. A pair of the piston-side accumulators and the piston-side pressure sensor are both connected to the pipeline between the third on-off solenoid valve and the piston sides of a pair of the double-acting cylinders. The annular-side accumulator and the annular-side pressure sensor are both connected to the pipeline between the second on-off solenoid valve and the annular sides of a pair of the double-acting cylinders. The position sensor is connected to the rocker arm of the suspension front axle. The first on-off solenoid valve is connected to an oil pump. The oil pump, the first on-off solenoid valve, the second on-off solenoid valve, the third on-off solenoid valve, the annular-side pressure sensor, the piston-side pressure sensor, the position sensor, the vehicle speed sensor, and the touch screen are all connected to the controller.

[0025] The beneficial effects of adopting the technical solution of the present invention are as follows: The controller, as a logical operation carrier, receives sensor signals, receives key message signals of the entire vehicle, and receives key signals of the large screen. According to the received signals, it calculates the operation instructions and control modes of the driver, and finally realizes the position adjustment and pressure adjustment of the front axle by controlling the on-off states of the three-way solenoid valves, achieving the desired front axle height control target and stiffness control target. The load of the suspension front axle can be calculated through the annular-side pressure and the piston-side pressure. The target position is calculated through the calculated load and the actual annular-side pressure. When the position or pressure exceeds the target range and lasts for a period of time, the position / pressure is adjusted back to the target value. By position adjustment and pressure adjustment, the position of the suspension front axle is maintained at the target position in the automatic mode, and at the same time, the annular side is adjusted to a pressure value with a certain spring stiffness coefficient. It enables the driver to obtain a better shock absorption effect and a more comfortable driving experience.

[0026] Advantages of additional aspects of the present invention will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the present invention. Brief Description of the Drawings

[0027] Figure 1 It is a schematic flow block diagram of the tractor suspension front axle control method provided by an embodiment of the present invention.

[0028] Figure 2Schematic diagram of mode switching provided by an embodiment of the present invention.

[0029] Figure 3 Schematic diagram of the structure of a tractor suspended front axle control system provided by an embodiment of the present invention.

[0030] Explanation of the reference numerals in the drawings: 1. Double-acting cylinder; 2. Piston-side accumulator; 3. Ring-side accumulator; 4. First switching solenoid valve; 5. Second switching solenoid valve; 6. Third switching solenoid valve. Specific implementation manners

[0031] The principles and features of the present invention will be described below with reference to the accompanying drawings. The illustrated embodiments are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0032] As Figure 1 shown, an embodiment of the present invention provides a method for controlling a tractor suspended front axle, including: in the automatic mode, obtaining the actual position of the suspended front axle, the ring-side pressure of the cylinder, and the piston-side pressure of the cylinder; obtaining the load of the suspended front axle according to the ring-side pressure and the piston-side pressure of the cylinder; obtaining the target position of the automatic mode according to the load of the suspended front axle and the ring-side pressure of the cylinder; determining the adjustment strategy of the automatic mode according to the actual position of the suspended front axle, the ring-side pressure of the cylinder, the piston-side pressure of the cylinder, the target position of the automatic mode, and the preset pressure range of the cylinder; and adjusting the suspended front axle according to the adjustment strategy of the automatic mode. In the locked mode, the piston side is depressurized to keep the position of the front axle unchanged; in the manual mode, the position of the front axle is manually adjusted; and the logical switching between the three modes.

[0033] The beneficial effects of adopting the technical solution of the present invention are: the load of the suspended front axle can be calculated through the ring-side pressure and the piston-side pressure, the target position is calculated through the calculated load and the actual ring-side pressure, and when the position or pressure exceeds the target range and lasts for a period of time, the position / pressure is adjusted back to the target value. By adjusting the position and pressure, the position of the suspended front axle is maintained at the target position in the automatic mode, and at the same time, the ring side is adjusted to a pressure value with a certain spring stiffness coefficient. It enables the driver to obtain a better shock absorption effect and a more comfortable driving experience.

[0034] As a key piece of machinery in agricultural production, the main operating site of a tractor is farmland. Due to the uneven ground surface, the tractor experiences severe jolts during travel, which not only affects the operating efficiency of the tractor but also reduces the comfort of the driver. By installing a suspended front axle, the front wheels of the tractor can be separated from the chassis. This separation brings two main benefits: Firstly, components such as the chassis and the cab are less affected by the impacts from the ground through the wheels, thus providing a smoother driving experience for the driver and significantly increasing the service life. Secondly, it makes the variation of the vertical wheel force more gradual, reduces the skidding phenomenon, and improves the transmission efficiency of the traction force. When a vehicle is configured with these functions, compared with a tractor without a suspended front axle, it can travel and operate at a higher speed.

[0035] The design of the suspended front axle of a tractor follows the principle of driving safety; the setting of its performance parameters is based on the human perception standard of vibration and refers to the characteristics of a single-mass oscillator under base excitation; the design of commissioning and testing aims to ensure that the tractor meets the actual usage requirements.

[0036] Furthermore, the step of determining the adjustment strategy for the automatic mode according to the actual position of the suspended front axle, the annular-side pressure of the oil cylinder, the piston-side pressure of the oil cylinder, the target position of the automatic mode, and the preset pressure range of the oil cylinder includes: when the actual position of the suspended front axle exceeds the target position of the automatic mode and lasts for a first preset time, adjusting the actual position of the suspended front axle back to the target position of the automatic mode; when the actual pressure of the oil cylinder exceeds the preset pressure range of the oil cylinder and lasts for a second preset time, adjusting the actual pressure of the oil cylinder back to the preset pressure range of the oil cylinder.

[0037] The beneficial effect of adopting the above further technical solution is that the load of the suspended front axle can be calculated through the annular-side pressure and the piston-side pressure, the target position can be calculated through the calculated load and the actual annular-side pressure, and after the position or pressure exceeds the target range and lasts for a period of time, the position / pressure is adjusted back to the target value. Keep the position of the suspended front axle at the target position of the automatic mode.

[0038] Furthermore, the step of adjusting the actual pressure of the oil cylinder back to the preset pressure range of the oil cylinder when the actual pressure of the oil cylinder exceeds the preset pressure range of the oil cylinder and lasts for a second preset time includes: when the actual annular-side pressure of the oil cylinder exceeds the preset annular-side pressure range of the oil cylinder and lasts for a second preset time, adjusting the actual annular-side pressure of the oil cylinder back to the first preset annular-side pressure range of the oil cylinder.

[0039] The beneficial effects of adopting the above further technical solution are as follows: the load of the suspension front axle can be calculated through the ring side pressure and the piston side pressure, the target position is calculated through the obtained load and the actual ring side pressure, and when the position or pressure exceeds the target range and lasts for a period of time, the position / pressure is adjusted back to the target value. The ring side is adjusted to a pressure value with a certain spring stiffness coefficient.

[0040] Further, the target position of the automatic mode is adjacent to 50% of the total elongation of the oil cylinder, and the preset pressure range of the oil cylinder is the pressure range with a preset spring stiffness coefficient on the ring side of the oil cylinder.

[0041] The beneficial effects of adopting the above further technical solution are as follows: by position adjustment and pressure adjustment, the position of the suspension front axle is maintained at about 50%, and at the same time, the ring side is adjusted to a pressure value with a certain spring stiffness coefficient.

[0042] Further, the step of adjusting the suspension front axle according to the adjustment strategy of the automatic mode includes: first, adjusting the actual position of the suspension front axle; when the actual position of the suspension front axle is adjacent to the target position of the automatic mode, adjusting the actual pressure of the oil cylinder.

[0043] The beneficial effects of adopting the above further technical solution are as follows: when controlling and adjusting in the automatic mode, the position and the ring side pressure of the suspension front axle are adjusted simultaneously. Position control is carried out first and then ring side pressure control. In order to avoid repeated control, the ring side pressure control is advanced before the position reaches 50%, and the change of the ring side pressure is controlled by the on / off of three solenoid valves.

[0044] Further, according to the range where the actual vehicle speed is located, or by receiving a button instruction, the target mode is determined; according to the target mode and the current mode, a mode switching strategy is determined; according to the mode switching strategy, the current mode is switched to the target mode.

[0045] The beneficial effects of adopting the above further technical solution are as follows: according to the actual vehicle speed and the button instruction, the switching between modes is adaptively adjusted to ensure the stability of the suspension front axle control system of the tractor.

[0046] Further, the step of determining the mode switching strategy according to the target mode and the current mode includes: in the manual mode, when the vehicle speed is greater than the first preset speed, the manual mode is switched to the automatic mode; in the locked mode, when the vehicle speed is greater than the second preset speed, the locked mode is switched to the automatic mode; when the vehicle speed is not greater than the third preset speed, the automatic mode is switched to the locked mode.

[0047] The beneficial effects of adopting the above further technical solution are as follows: In the manual mode, when the vehicle speed is greater than the first preset speed, to ensure the shock absorption effect of the floating front axle of the tractor, the tractor floating front axle control system automatically switches from the manual mode to the automatic mode, and will not return to the manual mode after the vehicle stops and the front axle will not continue to be adjusted; In the locked mode, when the vehicle speed is greater than the second preset speed, the tractor floating front axle control system switches from the locked mode to the automatic mode, and when the vehicle speed drops to the third preset speed, the tractor floating front axle control system returns to the locked mode.

[0048] As Figure 2 shown, receive the lock button signal to enter the locked mode; receive the auto button signal for the automatic mode; receive the manual button signal for the manual mode.

[0049] In the locked mode, when the vehicle speed is greater than 20 km / h or the automatic mode button is pressed, enter the automatic mode;

[0050] In the automatic mode, when the vehicle speed is less than 18 km / h or the locked mode button is pressed, enter the locked mode.

[0051] In the automatic mode, when the manual mode button is pressed, enter the manual mode.

[0052] In the manual mode, when the locked mode button is pressed, enter the locked mode.

[0053] In the manual mode, when the vehicle speed is greater than 2 km / h or the automatic mode button is pressed, enter the automatic mode.

[0054] Furthermore, the step of determining the mode switching strategy according to the target mode and the current mode further includes: In the manual mode, switch the manual mode to the automatic mode or the locked mode according to the button instruction; In the automatic mode, switch the automatic mode to the manual mode or the locked mode according to the button instruction; In the locked mode, switch the locked mode to the automatic mode according to the button instruction.

[0055] The beneficial effects of adopting the above further technical solution are as follows: To ensure the stability of the tractor floating front axle control system, logical restrictions are also imposed on the mode switching. In the manual mode, it can be switched to the automatic mode and the locked mode through the button. In the automatic mode, it can be switched to the manual mode and the locked mode through the button. While in the locked mode, it can only be switched to the automatic mode through the button and cannot enter the manual mode.

[0056] Further, when switching to the locking mode, the piston side pressure of the release cylinder is released, so that the cylinder contracts to 0% of the total elongation of the cylinder; when the piston side pressure of the cylinder drops to 0 bar and lasts for the third preset time, oil is supplied to the ring side of the cylinder; when the ring side pressure of the cylinder is greater than the second preset ring side pressure of the cylinder, the oil supply to the ring side of the cylinder is stopped, and the combination of the locking mode is completed; after the key is powered off, the sub-state of the locking mode is stored in the controller, and the sub-state of the previous locking mode is read after powering on again; if the previous state was the combination state of the locking mode or during the combination process, the locking mode will be automatically entered after the engine is started this time; in the manual mode, when the actual telescopic position of the cylinder is within the range from the first preset position to the second preset position, oil is supplied to the piston side of the cylinder or the piston side of the cylinder is drained according to the rising button command or the falling button command; in the manual mode, when the actual telescopic position of the cylinder exceeds the range from the first preset position to the second preset position and lasts for the fourth preset time, the piston side of the cylinder and the ring side of the cylinder are closed.

[0057] The beneficial effects of adopting the above further technical solutions are as follows: The locking mode mainly fixes the position of the floating front axle at 0%, making the front axle become a rigid front axle to adapt to more required working conditions. The manual mode is mainly used to cooperate with the driver to hitch the front-mounted implement and adjust the position of the front axle.

[0058] The control modes of the floating front axle mainly include: automatic mode control, manual mode control, locking mode control, and accumulator test mode.

[0059] 1. The automatic mode is to enable the driver to obtain better shock absorption effects and a more comfortable driving experience.

[0060] The automatic mode mainly maintains the position of the floating bridge (floating front axle) at about 50% (the position of the floating front axle, which can also be the elongation of the cylinder, the target position of the automatic mode) through position adjustment and pressure adjustment, and at the same time adjusts the ring side (the ring side of the cylinder) to a pressure value with a certain spring stiffness coefficient. According to different loads, the pressure value will also have different changes.

[0061] The load of the front axle (floating front axle) can be calculated through the ring side pressure and the piston side pressure, and the target position (the target position of the automatic mode) is calculated through the calculated load and the actual ring side pressure. After the position or pressure exceeds the target range and lasts for a period of time, the position / pressure is adjusted back to the target value.

[0062] During the adjustment of the automatic mode control, the position and the ring side pressure of the floating front axle are adjusted simultaneously. The position control is carried out first and then the ring side pressure control. In order to avoid repeated control, the ring side pressure control is advanced before the position reaches 50%. The change of the ring side pressure is controlled by the on / off of three solenoid valves (the first switch solenoid valve, the second switch solenoid valve, and the third switch solenoid valve).

[0063] 2. The locking mode mainly fixes the position of the floating front axle at 0%, making the front axle a rigid front axle to adapt to more required working conditions.

[0064] After the locking mode is activated, the pressure on the piston side is first released. At the same time, the position (the position of the floating front axle, which can be the contraction amount of the oil cylinder) gradually drops to 0%. Then, after the pressure on the piston side drops to 0 bar and is maintained for 2 seconds (the third preset time), the oil supply to the ring side starts. After the pressure on the ring side is adjusted to be greater than the target ring side pressure, the oil supply to the ring side is closed, and the locking mode combination is completed. After the key is powered off, the sub - state of the locking mode is stored in the controller. When powered on again, the previous sub - state of the locking mode is read. If the previous state was in the locking mode combination state or during the combination process, then the locking mode will be automatically entered after the engine starts this time.

[0065] 3. The manual mode is mainly used to cooperate with the driver to hitch the front - mounted implement and adjust the position of the front axle.

[0066] In the manual mode, if the position ≤ 99% (the second preset position) and ≥ 1% (the first preset position), it is completely controlled according to the up / down buttons. That is, when the up button is pressed, the piston side is continuously supplied with oil, and when the down button is pressed, the piston is continuously drained of oil. If the position > 99% or < 1%, and it lasts for more than 1 second (the fourth preset time), then the piston side is closed and the ring side is closed.

[0067] At the same time, the switching between the three modes is also calculated inside the vehicle controller (the controller). In the manual mode, when the vehicle speed is greater than 2 km / h (the first preset speed), to ensure the shock - absorption effect of the floating front axle, the floating front axle system (the tractor floating front axle control system) automatically enters the automatic mode from the manual mode. When the vehicle stops, it will not return to the manual mode and the front axle will no longer be adjusted; in the locking mode, when the vehicle speed is greater than 20 km / h (the second preset speed), the floating front axle system (the tractor floating front axle control system) enters the automatic mode from the locking mode. When the vehicle speed drops to 18 km / h (the third preset speed), the system (the tractor floating front axle control system) returns to the locking mode. And to ensure the stability of the system (the tractor floating front axle control system), the switching of the mode also has logical restrictions. In the manual mode, it can be switched to the automatic mode and the locking mode through the button. In the automatic mode, it can be switched to the manual mode and the locking mode through the button. In the locking mode, it can only be switched to the automatic mode through the button and cannot enter the manual mode.

[0068] Such as Figure 3As shown in the figure, in addition, the present invention also provides a tractor suspension front axle control system for implementing the tractor suspension front axle control method described in any one of the above. The tractor suspension front axle control system includes: a pair of double-acting cylinders 1, a pair of piston-side accumulators 2, an annular-side accumulator 3, a first on-off solenoid valve 4, a second on-off solenoid valve 5, a third on-off solenoid valve 6, an annular-side pressure sensor, a piston-side pressure sensor, a position sensor, a vehicle speed sensor, a touch screen, and a controller. The first on-off solenoid valve 4 is respectively connected to the second on-off solenoid valve 5 and the third on-off solenoid valve 6 through pipelines. The second on-off solenoid valve 5 is connected to the annular side of a pair of the double-acting cylinders 1 through a pipeline. The third on-off solenoid valve 6 is connected to the piston side of a pair of the double-acting cylinders 1 through a pipeline. A pair of the piston-side accumulators 2 and the piston-side pressure sensor are both connected to the pipeline between the third on-off solenoid valve 6 and the piston side of a pair of the double-acting cylinders 1. The annular-side accumulator 3 and the annular-side pressure sensor are both connected to the pipeline between the second on-off solenoid valve 5 and the annular side of a pair of the double-acting cylinders 1. The position sensor is connected to the rocker arm of the suspension front axle. The first on-off solenoid valve 4 is connected to an oil pump. The oil pump, the first on-off solenoid valve 4, the second on-off solenoid valve 5, the third on-off solenoid valve 6, the annular-side pressure sensor, the piston-side pressure sensor, the position sensor, the vehicle speed sensor, and the touch screen are all connected to the controller.

[0069] The beneficial effects of adopting the technical solution of the present invention are as follows: The controller, as a logical operation carrier, receives sensor signals, receives key message signals of the whole vehicle, and receives key message signals of the large screen. According to the received signals, it calculates the operation instructions and control modes of the driver, and finally realizes the position adjustment and pressure adjustment of the front axle by controlling the on-off states of the three-way solenoid valves, so as to achieve the desired front axle height control target and stiffness control target. The load of the suspension front axle can be calculated through the annular-side pressure and the piston-side pressure. The target position is calculated through the calculated load and the actual annular-side pressure. When the position or pressure exceeds the target range and lasts for a period of time, the position / pressure is adjusted back to the target value. By position adjustment and pressure adjustment, the position of the suspension front axle is maintained at the target position in the automatic mode, and at the same time, the annular side is adjusted to a pressure value with a certain spring stiffness coefficient. This enables the driver to obtain a better shock absorption effect and a more comfortable driving experience.

[0070] The hardware components of the suspension front axle system (tractor suspension front axle control system) mainly include: 2 double-acting cylinders, 2 piston-side accumulators, 1 annular-side accumulator, 3 on-off solenoid valves (respectively controlling the pump, piston side, and annular side), 2 pressure sensors (respectively collecting piston-side pressure and annular-side pressure), and 1 position sensor (perceiving the angle of the front axle rocker arm and calculating the front axle position).

[0071] The vehicle controller (controller), as the carrier of logical operations, receives three-way sensor signals, the button signals (up, down, automatic, lock) from the large screen, and the key vehicle message signals (vehicle speed, engine speed, etc.). Based on all the received signals above, it calculates the driver's operation instructions and control modes, and finally realizes the position adjustment and pressure adjustment of the front axle (suspended front axle) by controlling the on / off states of three-way solenoid valves (the first switching solenoid valve, the second switching solenoid valve, and the third switching solenoid valve), so as to achieve the desired front axle height control target and stiffness control target.

[0072] The position of the suspended front axle is calculated by a position sensor. The position sensor selects a voltage-type sensor. When the front axle position drops to the lowest, the obtained voltage value is 0% of the position. When it rises to the highest, the voltage value is 100% of the position. The intermediate position is linearly calculated. The pressure of the suspended axle system (tractor suspended front axle control system) is obtained through a pressure sensor. The pressure sensor is a voltage-type sensor, and the value is linearly calculated.

[0073] The suspended front axle proposed in the present invention can greatly reduce the driver's bumpy feeling compared with the ordinary rigid front axle. At the same time, in the suspended front axle system (tractor suspended front axle control system) proposed in the present invention, the control method of keeping the front axle (suspended front axle) at the target position by controlling the pressures on both sides enables the suspended front axle of the system to be stable, and ensures that the tractor's tires are in full contact with the ground, improving the traction force. The stable traction force and shock absorption effect greatly improve the operation efficiency of the tractor, reducing slippage and idling.

[0074] Moreover, the automatic control mode (automatic mode) and the lock control mode (lock mode) proposed in the present invention can also make the user operate the suspended front axle more simply and efficiently, reducing the driver's burden, and also adapting to various operation requirements. The height and pressure can be adjusted according to different operation requirements, applicable to various tasks such as plowing, sowing, and transportation, and can match more implements and loads.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some 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 invention.

Claims

1. A control method for the suspended front axle of a tractor, characterized in that, Including: In the automatic mode, obtain the actual position of the floating front axle, the annular side pressure of the oil cylinder, and the piston side pressure of the oil cylinder; Obtain the load of the floating front axle according to the annular side pressure and the piston side pressure of the oil cylinder; Obtain the target position of the automatic mode according to the load of the floating front axle and the annular side pressure of the oil cylinder; Determine the adjustment strategy of the automatic mode according to the actual position of the floating front axle, the annular side pressure of the oil cylinder, the piston side pressure of the oil cylinder, the target position of the automatic mode, and the preset pressure range of the oil cylinder; Adjust the floating front axle according to the adjustment strategy of the automatic mode.

2. The control method of a floating front axle of a tractor according to claim 1, wherein The step of determining the adjustment strategy of the automatic mode according to the actual position of the floating front axle, the annular side pressure of the oil cylinder, the piston side pressure of the oil cylinder, the target position of the automatic mode, and the preset pressure range of the oil cylinder includes: When the actual position of the floating front axle exceeds the target position of the automatic mode and lasts for the first preset time, adjust the actual position of the floating front axle back to the target position of the automatic mode; When the actual pressure of the oil cylinder exceeds the preset pressure range of the oil cylinder and lasts for the second preset time, adjust the actual pressure of the oil cylinder back to the preset pressure range of the oil cylinder.

3. A control method for a floating front axle of a tractor according to claim 2, characterized in that, The step of adjusting the actual pressure of the oil cylinder back to the preset pressure range of the oil cylinder when the actual pressure of the oil cylinder exceeds the preset pressure range of the oil cylinder and lasts for the second preset time includes: when the actual annular side pressure of the oil cylinder exceeds the preset annular side pressure range of the oil cylinder and lasts for the second preset time, adjust the actual annular side pressure of the oil cylinder back to the first preset annular side pressure range by opening or closing the state of the annular side valve core.

4. A control method for a floating front axle of a tractor according to claim 1, characterized in that, The target position of the automatic mode is 50% of the middle position of the oil cylinder, and the preset pressure range of the oil cylinder is the pressure range with a preset spring stiffness coefficient on the annular side of the oil cylinder.

5. A control method for a floating front axle of a tractor according to claim 1, characterized in that, The step of adjusting the floating front axle according to the adjustment strategy of the automatic mode includes: First, adjust the actual position of the floating front axle; When the actual position of the floating front axle is close to the target position of the automatic mode, adjust the actual pressure of the oil cylinder.

6. A control method for a floating front axle of a tractor according to claim 1, characterized in that Judge the target mode according to the range of the actual vehicle speed or receive a button command; Determine the mode switching strategy according to the target mode and the current mode; Switch the current mode to the target mode according to the mode switching strategy.

7. A control method for a floating front axle of a tractor according to claim 6, characterized in that, The step of determining the mode switching strategy according to the target mode and the current mode includes: In the manual mode, when the vehicle speed is greater than the first preset speed, switch the manual mode to the automatic mode; In the locked mode, when the vehicle speed is greater than the second preset speed, switch the locked mode to the automatic mode; When the vehicle speed drops to the third preset speed, switch the automatic mode to the locked mode.

8. A control method for a floating front axle of a tractor according to claim 6, characterized in that, The step of determining the mode switching strategy according to the target mode and the current mode further includes: In the manual mode, switch the manual mode to the automatic mode or the locked mode according to the button command; In the automatic mode, switch the automatic mode to the manual mode or the locked mode according to the button command; In the locked mode, the locked mode can only be switched to the automatic mode according to a button command.

9. A control method for a floating front axle of a tractor according to claim 1, characterized in that When switching to the locked mode, the piston-side pressure of the oil cylinder is released, so that the oil cylinder contracts to 0% of the total elongation of the oil cylinder; When the piston-side pressure of the oil cylinder drops to 0 bar and lasts for a third preset time, oil is supplied to the ring side of the oil cylinder; When the pressure on the ring side of the oil cylinder is greater than the second preset ring-side pressure of the oil cylinder, the oil supply to the ring side of the oil cylinder is stopped, and the locked mode combination is completed; After the key is powered off, the sub-state of the locked mode is stored in the controller, and the sub-state of the locked mode read last time is read after power-on again; If it was in the locked mode combination state or during the combination process last time, it automatically enters the locked mode after the engine starts this time; In the manual mode, when the actual telescopic position of the oil cylinder is within the range from the first preset position to the second preset position, oil is supplied to the piston side of the oil cylinder or the piston side of the oil cylinder is drained according to an up button command or a down button command; In the manual mode, when the actual telescopic position of the oil cylinder exceeds the range from the first preset position to the second preset position and lasts for a fourth preset time, the piston side of the oil cylinder and the ring side of the oil cylinder are closed.

10. A suspension front axle control system for a tractor, characterized in that, For implementing the control method for the floating front axle of a tractor according to any one of claims 1 to 9, the floating front axle control system of the tractor includes: a pair of double-acting oil cylinders, a pair of piston-side accumulators, a ring-side accumulator, a first switching solenoid valve, a second switching solenoid valve, a third switching solenoid valve, a ring-side pressure sensor, a piston-side pressure sensor, a position sensor, a vehicle speed sensor, a multi-functional control screen, and a controller. The first switching solenoid valve is respectively connected to the second switching solenoid valve and the third switching solenoid valve through pipelines. The second switching solenoid valve is connected to the ring sides of the pair of double-acting oil cylinders through a pipeline. The third switching solenoid valve is connected to the piston sides of the pair of double-acting oil cylinders through a pipeline. The pair of piston-side accumulators and the piston-side pressure sensor are both connected to the pipeline between the third switching solenoid valve and the piston sides of the pair of double-acting oil cylinders. The ring-side accumulator and the ring-side pressure sensor are both connected to the pipeline between the second switching solenoid valve and the ring sides of the pair of double-acting oil cylinders. The position sensor is connected to the rocker arm of the floating front axle. The first switching solenoid valve is connected to an oil pump. The oil pump, the first switching solenoid valve, the second switching solenoid valve, the third switching solenoid valve, the ring-side pressure sensor, the piston-side pressure sensor, the position sensor, the vehicle speed sensor, and the touch screen are all connected to the controller.

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