Electro-hydraulic control system and tractor

Abstract

The present invention relates to an electro-hydraulic control system and a tractor, comprising a steering device, a multi-way valve device, a variable plunger pump and a steering priority valve, wherein an oil outlet of the variable plunger pump is connected to an oil inlet of the steering priority valve through a pipeline, and two oil outlets of the steering priority valve are respectively connected to an oil inlet of the steering device and an oil inlet of the multi-way valve device through pipelines. The beneficial effects of the present invention are that it has the characteristics of fast response speed, high control accuracy, convenient operation, etc., and simplifies the hydraulic pipeline; it has a constant speed control function, and can switch between high maneuverability or high economy modes; it improves the working performance and service life of the wet clutch; the constant power function can ensure that the engine works in the best economic state.

Description

Technical Field

[0001] The present invention relates to the technical field of tractors, and in particular to an electro-hydraulic control system and a tractor. Background Art

[0002] As the most important member of the agricultural machinery sector, tractors and related products have received key support from the state. After more than ten years of development, the production technology and R&D capabilities of tractor manufacturers have been rapidly improved, and intelligent tractor products have emerged in an endless stream. The outstanding performance of mechatronics and hydraulic integration in tractor products - the product performance, product quality and operating comfort have been greatly improved.

[0003] Traditional tractors may not have electro-hydraulic control systems, but modern tractors cannot do without them. In addition, large and medium-sized tractors have begun to be equipped with load-sensitive electro-hydraulic control systems, and the corresponding products have greatly improved in energy conservation and emission reduction.

[0004] The electro-hydraulic control system includes a closed-center load sensing system and an open quantitative system. Among them, the load-sensitive system transmits the maximum load pressure of the steering system and the multi-way valve working system back to the variable displacement device of the variable piston pump through the load sensing module. After the variable displacement device compares the sum of the load pressure and the fixed spring force with the outlet pressure of the variable piston pump, it automatically adjusts the displacement of the variable piston pump to provide the power required by the working device, thereby achieving the purpose of energy saving and emission reduction. In addition, in order to ensure the normal operation of the transmission box and the wet clutch, the open quantitative system is equipped with an oil cooling system and a lubrication system. The above-mentioned prior art has the following disadvantages:

[0005] a. Under any working condition, the pump outlet pressure must be higher than the load pressure. The difference is the pressure value corresponding to the fixed spring force in the variable displacement device (about 20 bar). There is a certain power loss, and the greater the flow rate required by the system, the greater the power loss;

[0006] b. The maximum load is transmitted to the pump variable mechanism through the hydraulic pipeline, which has a slow dynamic response and causes fluctuations in the low-pressure control oil source;

[0007] c. The load sensing module is realized through hydraulic pipelines, and the pipeline layout is relatively complicated;

[0008] d. Power shift input pressure fluctuations will affect the control performance of the clutch. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide an electro-hydraulic control system and a tractor, aiming to solve the problems in the prior art.

[0010] The technical solution of the present invention to solve the above technical problems is as follows:

[0011] An electro-hydraulic control system comprises a steering device, a multi-way valve device, a variable plunger pump and a steering priority valve, wherein the oil outlet of the variable plunger pump is connected to the oil inlet of the steering priority valve through a pipeline, and the two oil outlets of the steering priority valve are respectively connected to the oil inlet of the steering device and the oil inlet of the multi-way valve device through pipelines.

[0012] The beneficial effects of the present invention are as follows: during use, the oil is sent to the steering priority valve through the variable plunger pump, and then divided into two parts to be supplied to the steering device and the multi-way valve device respectively, and finally the steering device and the multi-way valve device complete the corresponding actions; during operation, the flow rate of the output oil is adjusted by the variable plunger pump to meet the different operation requirements of the steering device and the multi-way valve device; in addition, the steering device is given priority to be supplied with oil through the steering priority valve, and the multi-way valve device is supplied with oil after the oil demand of the steering device is met. The present invention has a compact structure, a reasonable design, and reduces energy loss.

[0013] Based on the above technical solution, the present invention can also be improved as follows.

[0014] Furthermore, it also includes a lubrication pump, a power shift device and a transmission box filled with oil, the oil inlet of the variable piston pump is connected to the transmission box through a pipeline; the oil inlet of the lubrication pump is connected to the pipeline between the transmission box and the variable piston pump through a pipeline, and its oil outlet is connected to the oil inlet of the power shift device through a pipeline.

[0015] The beneficial effect of adopting the above further solution is that the oil is sent to the power shift device through the lubrication pump to complete the shifting action; in addition, the lubrication pump and the variable piston pump are simultaneously supplied with oil through the transmission box, simplifying the pipeline.

[0016] Furthermore, it also includes a cylinder control device, and the oil inlet of the cylinder control device is connected to the pipeline between the power shift device and the lubrication pump through a pipeline.

[0017] The beneficial effect of adopting the above further scheme is that the lubrication pump can simultaneously deliver oil to the cylinder control device and the power shift device respectively, thereby completing the shifting action and the cylinder control action; at this time, the lubrication pump can simultaneously provide oil to the cylinder control device and the power shift device through one pipeline, thereby simplifying the pipeline.

[0018] Furthermore, it also includes an LS pressure controller and an LS pressure control valve, the oil inlet of the LS pressure control valve is connected to the second oil outlet of the variable piston pump through a pipeline, and the oil outlet is connected to the pipeline between the lubrication pump and the power shift device through a pipeline; the LS pressure control valve, the steering device and the multi-way valve device are respectively communicatively connected to the LS pressure controller.

[0019] The beneficial effect of adopting the above further scheme is that during operation, the LS pressure controller outputs instructions to adjust the LS pressure control valve control oil port pressure value according to the difference between the variable piston pump outlet pressure and the maximum working pressure of the steering device and / or the multi-way valve device, thereby enabling the variable piston pump to provide oil flow on demand. The different pressure differences can achieve two operating modes: high economy and high maneuverability. The high economy mode greatly reduces power loss, and the high maneuverability mode can achieve micro-control of the steering device and / or the multi-way valve device.

[0020] Furthermore, the power shift device includes at least one shift mechanism, and the oil inlet of each shift mechanism is connected to the oil outlet of the lubrication pump through a pipeline.

[0021] The beneficial effect of adopting the above further solution is that the oil is delivered to the shift mechanism through the lubrication pump to complete the shifting action.

[0022] Furthermore, the power shift device also includes a power shift controller, each of the shift mechanisms includes a shift valve and a wet clutch, the oil inlet of each shift valve is connected to the oil outlet of the lubrication pump through a pipeline, and the oil outlet is connected to the corresponding wet clutch through a pipeline; each of the shift valves is respectively communicatively connected to the power shift controller.

[0023] The beneficial effect of adopting the above further solution is that during operation, the corresponding shift mechanism shift instruction is manually input in advance through the power shift controller, and the power shift controller controls the shift valve according to the corresponding instruction to realize the wet clutch action.

[0024] Furthermore, the cylinder control device includes an AMT cylinder control valve group and an accumulator, the oil inlet of the AMT cylinder control valve group is connected to the pipeline between the lubrication pump and the power shift device through an energy storage pipeline; the accumulator is connected to the energy storage pipeline through a pipeline.

[0025] The beneficial effect of adopting the above-mentioned further scheme is that the oil is delivered to the AMT cylinder control valve group and the accumulator through the lubrication pump, so that the AMT cylinder control valve group can complete the corresponding actions and fill the accumulator; when the oil supplied by the lubrication pump to the AMT cylinder control valve group is not sufficient to meet its operation, the accumulator can supply the pre-stored oil to the AMT cylinder control valve group to enable normal operation, thereby ensuring working performance and service life.

[0026] Furthermore, the cylinder control device also includes a cylinder controller, and the AMT cylinder control valve group is communicatively connected to the cylinder controller.

[0027] The beneficial effect of adopting the above further scheme is that during operation, corresponding instructions are input to the cylinder controller manually or through a built-in program, and the cylinder controller controls the action of the AMT cylinder control valve group according to the corresponding instructions.

[0028] Furthermore, the AMT cylinder control valve group includes at least one clutch control valve and at least one control clutch corresponding to the clutch control valve one by one, the oil inlet of each clutch control valve is connected to the pipeline between the lubrication pump and the power shift device through a pipeline, and the oil outlet is connected to the corresponding control clutch through a pipeline; each clutch control valve is respectively communicatively connected to the cylinder controller.

[0029] The beneficial effect of adopting the above further solution is that during operation, corresponding instructions are input into the cylinder controller manually or through a built-in program, and the cylinder controller controls the clutch control valve to control the clutch action according to the corresponding instructions.

[0030] Furthermore, the AMT cylinder control valve group includes at least one cylinder mechanism, and the oil inlet of each cylinder mechanism is connected to the pipeline between the lubrication pump and the power shift device through a pipeline, and is communicatively connected to the cylinder controller.

[0031] The beneficial effect of adopting the above further scheme is that during operation, the corresponding parameters are manually input in advance through the cylinder controller, and the cylinder controller controls the movement of the cylinder mechanism according to the corresponding parameters; in this process, the oil pressure signal in the cylinder mechanism will be transmitted to the LS pressure control valve, and the LS pressure control valve will send the corresponding pressure signal to the LS pressure controller. The LS pressure controller controls the LS pressure control valve according to the signal to adjust the amount of oil output by the variable piston pump, thereby avoiding excessive oil input and saving energy.

[0032] Furthermore, the load sensing port on the steering device is connected to the steering priority valve through a pipeline, and a steering pressure sensor is fixedly installed on the pipeline between the two; a multi-way valve pressure sensor is connected to the load sensing port on the multi-way valve device, and the steering pressure sensor and the multi-way valve pressure sensor are respectively communicated with the LS pressure controller.

[0033] The beneficial effect of adopting the above further scheme is that the actual working pressure of the steering device is detected by the steering pressure sensor, and the actual working pressure of the multi-way valve device is detected by the multi-way valve pressure sensor. The two respectively send corresponding pressure signals to the LS pressure controller, and the LS pressure controller controls the LS pressure control valve to adjust the output flow of the variable plunger pump according to the signal, thereby reducing the input of excessive oil and saving energy consumption. When the opening of the steering device and the multi-way valve device remains unchanged, when the actual working pressure of the steering device or the actual working pressure of the multi-way valve device increases / decreases, the LS pressure controller increases / decreases the output flow of the variable plunger pump by reducing / increasing the LS pressure control valve control oil port pressure value, ensuring that the difference between the actual working pressure of the steering device or the actual working pressure of the multi-way valve device and the outlet pressure of the variable pump reaches a constant value, thereby realizing constant speed control. In the constant power control mode, after the output power of the multi-way valve device reaches the constant power control point, when the actual working pressure of the multi-way valve device increases, the LS pressure controller increases the LS pressure control valve control oil port pressure value, reduces the output flow of the variable plunger pump, and realizes constant power control of the output power of the multi-way valve device.

[0034] Furthermore, a variable pump outlet pressure sensor is fixedly installed on the pipeline between the variable piston pump and the steering priority valve, and the variable pump outlet pressure sensor is communicatively connected with the LS pressure controller.

[0035] The beneficial effect of adopting the above further scheme is to detect the pressure of the oil at the oil outlet of the variable piston pump through the variable pump outlet pressure sensor, and send the corresponding signal to the LS pressure controller. The LS pressure controller controls the LS pressure control valve according to the signal to adjust the amount of oil output by the variable piston pump, thereby avoiding excessive oil input, saving energy and achieving more precise control.

[0036] Furthermore, it also includes a lubrication device, the oil inlet of the lubrication device is connected to the pipeline between the lubrication pump and the power shift device through a lubrication pipeline; the oil outlet of the steering device is connected to the lubrication pipeline through a pipeline.

[0037] The beneficial effect of adopting the above further scheme is that the oil is sent to the lubrication device for lubrication operation through the lubrication pump, which further simplifies the pipeline; in addition, the return oil in the steering device is supplied to the lubrication device for lubrication operation through the corresponding pipeline, saving resources.

[0038] Furthermore, an overflow valve is fixedly installed on the lubrication pipeline.

[0039] The beneficial effect of adopting the above further solution is to maintain the pre-valve pressure through the overflow valve, which is used to provide control pressure oil to the LS pressure control valve, the shift valve and the AMT cylinder control valve group.

[0040] Furthermore, it also includes a boost pump and a bypass control valve group, the oil inlet of the boost pump is connected to the pipeline between the transmission box and the variable piston pump through a pipeline, the oil outlet 1 is connected to the oil inlet of the variable piston pump through a pipeline, the oil outlet 2 is connected to the oil inlet of the bypass control valve group through a pipeline, the oil outlet 1 of the bypass control valve group is connected to the position of the lubrication pipeline corresponding to the overflow valve and the lubrication device through a pipeline, and the oil outlet 2 is connected to the pipeline between the boost pump and the bypass control valve group through a pipeline; the oil inlet of the lubrication pump is connected to the pipeline between the boost pump and the transmission box through a pipeline.

[0041] The beneficial effect of adopting the above further scheme is that the booster pump provides oil to the variable plunger pump, so that there is enough oil at the oil inlet of the variable plunger pump, ensuring the oil absorption performance of the variable plunger pump and improving its working efficiency; on the other hand, the booster pump replenishes oil to the lubricating device to ensure that the lubricating device obtains sufficient lubricating oil. When the variable plunger pump does not output oil, the bypass control valve group can not only flow part of the oil back to the oil inlet of the booster pump, but also ensure that the pressure at the oil inlet of the variable plunger pump is not greater than a certain safety pressure.

[0042] Furthermore, an oil suction pressure switch is fixedly installed at the connection point of the pipeline between the lubrication pump, the boost pump and the transmission box.

[0043] The beneficial effect of adopting the above further scheme is to supply oil to the entire hydraulic system through the transmission box, and monitor the pressure of the booster pump and lubrication pump oil inlet pipeline through the oil suction pressure switch. When the pressure is too high, manual maintenance or repair is required.

[0044] Furthermore, the lubrication device includes a lubrication control oil channel and a cooler, the inlet of the cooler is connected to the outlet of the lubrication pipeline, and its outlet is connected to the lubrication control oil channel through a pipeline; the oil outlet of the steering device is connected to the pipeline between the lubrication control oil channel and the cooler through a pipeline.

[0045] The beneficial effect of adopting the above further scheme is that the oil sent by the lubrication pump is cooled by the cooler and then sent to the lubrication control oil channel for lubrication, thereby ensuring the lubrication effect.

[0046] Furthermore, the lubrication device also includes a lubrication bypass valve group, the inlet of the lubrication bypass valve group is connected to the position of the lubrication pipeline close to the cooler through a pipeline, and the outlet of the lubrication bypass valve group is connected to the pipeline between the cooler and the lubrication control oil channel through a pipeline; the lubrication bypass valve group is also provided with a pressure relief port.

[0047] The beneficial effect of adopting the above-mentioned further scheme is that the lubrication bypass valve group is used as a backup lubrication route. When the cooler is blocked, the oil enters the lubrication control oil channel through the lubrication bypass valve group to ensure the normal progress of the lubrication operation; and, when the inlet pressure of the lubrication control oil channel is too high, part of the oil is discharged through the pressure relief port of the lubrication bypass valve group for pressure relief treatment to ensure the normal pressure inside the system.

[0048] Furthermore, it also includes a safety valve, the oil inlet of the safety valve is connected to the pipeline between the steering priority valve and the multi-way valve device through a pipeline, the oil outlet of the multi-way valve device is connected to the return oil pipeline, and the oil outlet of the safety valve is connected to the return oil pipeline through a pipeline.

[0049] The beneficial effect of adopting the above further scheme is that when the pressure of the oil in the corresponding pipeline is lower than the set pressure, all the oil enters the multi-way valve device; when the pressure of the oil in the corresponding pipeline is higher than the set pressure, part of the oil enters the multi-way valve device to ensure the normal operation of the multi-way valve device, and the other part of the oil is returned through the safety valve to avoid excessive pressure in the system, which is safe and reliable.

[0050] The present invention also relates to a tractor, comprising the electro-hydraulic control system as described above.

[0051] The beneficial effect of adopting the above further scheme is to provide a tractor with the above electro-hydraulic control system, which has the characteristics of fast response speed, high control accuracy, easy operation, etc., and simplifies the hydraulic pipeline; has a constant speed control function, and can switch between high maneuverability or high economy mode; improves the working performance and service life of the wet clutch; and the constant power function can ensure that the engine works in the best economic state. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a structural schematic diagram of the present invention.

[0053] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0054] 1. Multi-way valve pressure sensor; 2. Steering pressure sensor; 3. Steering priority valve; 4. LS pressure controller; 5. Variable pump outlet pressure sensor; 6. LS pressure control valve; 7. Oil pressure filter; 8. Booster pump; 9. Suction pressure switch; 10. Transmission box; 11. Suction filter; 12. Variable plunger pump; 13. Lubrication pump; 14. Lubrication pump pressure filter; 15. Safety valve; 16. Multi-way valve device; 17. Shift valve; 18. Wet clutch; 19. Power shift control Controller; 20. Lubrication bypass valve group; 21. Lubrication control oil channel; 22. Cooler; 23. Accumulator; 24. Power shift pressure sensor; 25. Check valve; 26. Four-wheel drive control clutch; 27. Cylinder controller; 28. AMT cylinder control valve group; 29. ​​Differential control clutch; 30. Control cylinder; 31. PTO control clutch; 32. PTO brake control clutch; 33. Bypass control valve group; 34. Overflow valve; 35. Steering cylinder; 36. Full hydraulic steering gear. DETAILED DESCRIPTION

[0055] The principles and features of the present invention are described below in conjunction with the accompanying drawings and specific embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0056] like Figure 1 As shown, the present invention provides an electro-hydraulic control system, including a steering device, a multi-way valve device 16, a variable plunger pump 12 and a steering priority valve 3. The oil outlet of the variable plunger pump 12 is connected to the oil inlet of the steering priority valve 3 through a pipeline, and the two oil outlets of the steering priority valve 3 are respectively connected to the oil inlet of the steering device and the oil inlet of the multi-way valve device 16 through pipelines. During use, the oil is sent to the steering priority valve 3 by the variable plunger pump 12, and then divided into two parts and supplied to the steering device and the multi-way valve device 16 respectively, and finally the steering device and the multi-way valve device 16 complete the corresponding action; during operation, the flow rate of the output oil is adjusted by the variable plunger pump 12 to meet the different operating requirements of the steering device and the multi-way valve device 16. In addition, the steering device is preferentially provided with oil through the steering priority valve 3, and the multi-way valve device 16 is provided with oil after the oil demand of the steering device is met. The present invention has a compact structure, a reasonable design, and reduces energy loss.

[0057] Example 1

[0058] On the basis of the above structure, the present embodiment further includes a lubrication pump 13, a power shift device and a transmission case 10 filled with oil. The oil inlet of the variable piston pump 12 is connected to the transmission case 10 through a pipeline; the oil inlet of the lubrication pump 13 is connected to the pipeline between the transmission case 10 and the variable piston pump 12 through a pipeline, and its oil outlet is connected to the oil inlet of the power shift device through a pipeline. During operation, the oil is sent to the power shift device through the lubrication pump 13 to complete the shifting action.

[0059] Example 2

[0060] On the basis of the above structure, the present embodiment further includes a cylinder control device, and the oil inlet of the cylinder control device is connected to the pipeline between the power shift device and the lubrication pump 13 through a pipeline. During operation, the lubrication pump 13 simultaneously delivers oil to the cylinder control device and the power shift device, respectively, to complete the shifting action and the cylinder control action; at this time, the lubrication pump 13 can simultaneously provide oil to the cylinder control device and the power shift device through one pipeline, thereby simplifying the pipeline.

[0061] Example 3

[0062] On the basis of the above-mentioned embodiments, this embodiment further includes an LS pressure controller 4 and an LS pressure control valve 6. The control oil port of the LS pressure control valve 6 is connected to the variable control oil cylinder connected to the oil outlet port 2 of the variable piston pump 12 through a pipeline, and its oil inlet is connected to the pipeline between the lubrication pump 13 and the power shift device through a pipeline; the LS pressure control valve 6, the steering device and the multi-way valve device 16 are respectively connected to the LS pressure controller 4 for communication. During operation, the LS pressure controller 4 outputs instructions to adjust the pressure value of the control oil port of the LS pressure control valve 6 according to the difference between the oil outlet port 1 pressure of the variable piston pump 12 and the maximum working pressure of the steering device and / or the multi-way valve device 16, thereby realizing the variable piston pump 12 to provide the oil flow on demand. The difference in pressure difference can realize two operating modes of high economy and high maneuverability. The high economy mode greatly reduces the power loss, and the high maneuverability mode can realize the micro-control of the steering device and / or the multi-way valve device 16.

[0063] When the above scheme is based on the scheme of Example 1, that is, the cylinder control device and the power shift device exist at the same time, the lubrication pump 13 supplies oil to the cylinder control device and the power shift device at the same time, and the oil inlet of the cylinder control device is connected to the pipeline between the LS pressure control valve 6 and the power shift device; when the above scheme is not based on the method of Example 1, that is, only one of the cylinder control device and the power shift device exists, the lubrication pump 13 is used to supply oil to the cylinder control device or the power shift device.

[0064] Example 4

[0065] Based on the third embodiment, in this embodiment, the power shift device includes at least one shift mechanism, and the oil inlet of each shift mechanism is connected to the oil outlet of the lubrication pump 13 through a pipeline. During operation, the oil is delivered to the shift mechanism through the lubrication pump 13 to complete the shifting action.

[0066] Example 5

[0067] On the basis of the fourth embodiment, in this embodiment, the power shift device further includes a power shift controller 19, each shift mechanism includes a shift valve 17 and a wet clutch 18, the oil inlet of each shift valve 17 is connected to the oil outlet of the lubrication pump 13 through a pipeline, and its control oil port is connected to the corresponding wet clutch 18 through a pipeline; each shift valve 17 is respectively connected to the power shift controller 19 for communication. During operation, the power shift controller 19 manually inputs the shift command of the corresponding shift mechanism in advance, and the power shift controller 19 controls the shift valve 17 according to the corresponding command to realize the action of the wet clutch 18

[0068] Example 6

[0069] On the basis of Example 4 or Example 5, preferably, in this embodiment, the power shift device includes a plurality of shift mechanisms distributed in parallel, the oil inlets of the plurality of shift valves 17 in the plurality of shift mechanisms are respectively connected to the oil inlet pipeline through pipelines, and the oil inlet end of the oil inlet pipeline is connected to the oil outlet of the lubrication pump 13 through the pipeline; at the same time, the oil outlets of the plurality of shift valves 17 in the plurality of shift mechanisms are respectively connected to the oil return pipeline through pipelines, and the oil return pipeline is connected to the oil return tank, so as to realize the rapid recovery of oil, thereby realizing the recycling of oil and saving resources.

[0070] In addition, the multiple shift valves 17 in the multiple shift mechanisms are respectively connected to the power shift controller 19 for communication, and the multiple shift valves 17 are controlled by the power shift controller 19 .

[0071] Example 7

[0072] On the basis of the third embodiment, in this embodiment, the cylinder control device includes an AMT cylinder control valve group 28 and an accumulator 23. The oil inlet of the AMT cylinder control valve group 28 is connected to the pipeline between the lubrication pump 13 and the power shift device through the accumulator pipeline; the accumulator 23 is connected to the accumulator pipeline through the pipeline. During operation, the lubrication pump 13 delivers oil to the AMT cylinder control valve group 28 and the accumulator, so that the AMT cylinder control valve group 28 can complete the corresponding action and the accumulator 23 can be filled with oil; in addition, when the oil supplied by the lubrication pump 13 to the AMT cylinder control valve group 28 is still surplus to meet its operation, the surplus oil is stored in the accumulator 23; when the oil supplied by the lubrication pump 13 to the AMT cylinder control valve group 28 is not sufficient to meet its operation, the accumulator 23 can supply the pre-stored oil to the AMT cylinder control valve group to enable normal operation, thereby ensuring the working performance and service life of each component.

[0073] Example 8

[0074] On the basis of Embodiment 7, in this embodiment, the cylinder control device further includes a cylinder controller 27, and the AMT cylinder control valve group 28 is communicatively connected to the cylinder controller 27. During operation, a corresponding instruction is input to the cylinder controller 27 manually or through a built-in program, and the cylinder controller 27 controls the AMT cylinder control valve group 28 to move according to the corresponding instruction.

[0075] Example 9

[0076] On the basis of Embodiment 8, in this embodiment, a power shift pressure sensor 24 is fixedly installed on the pipeline connecting the accumulator 23 and the AMT cylinder control valve group 28, and the power shift pressure sensor 24 is respectively connected to the cylinder controller 27 and the power shift controller 19. During operation, the oil pressure at the accumulator 23 is detected by the power shift pressure sensor 24, and the corresponding pressure signal is sent to the cylinder controller 27, and the cylinder controller 27 receives the corresponding pressure signal and compares the pressure signal with the pre-input pressure threshold, and analyzes and determines the size of the two pressure values; when the power shift pressure sensor 24 ≥ the pressure threshold, the cylinder controller 27 receives the signal sent by the staff operating button and performs the corresponding action to ensure the normal operation of the AMT cylinder control valve group 28; when the power shift pressure sensor 24 < the pressure threshold, the cylinder controller 27 receives the signal sent by the staff operating button, but the cylinder controller 27 does not perform the corresponding action, and the staff needs to perform maintenance to ensure the normal operation of the AMT cylinder control valve group 28.

[0077] Example 10

[0078] On the basis of Embodiment 8 or Embodiment 9, in this embodiment, the AMT cylinder control valve group 28 includes at least one clutch control valve and at least one control clutch corresponding to the clutch control valve. The oil inlet of each clutch control valve is connected to the pipeline between the lubrication pump 13 and the power shift device through a pipeline, and its oil outlet is connected to the corresponding control clutch through a pipeline; each clutch control valve is respectively connected to the cylinder controller 27 for communication. During operation, the corresponding instructions are input to the cylinder controller 27 in advance manually or through a built-in program, and the cylinder controller 27 controls the clutch control valve to control the clutch action according to the corresponding instructions.

[0079] Embodiment 11

[0080] On the basis of Example 10, in this embodiment, the AMT cylinder control valve group 28 includes a four-wheel drive control clutch 26 and a four-wheel drive clutch control valve, the oil inlet of the four-wheel drive clutch control valve is connected to the pipeline between the lubrication pump 13 and the power shift device through a pipeline, and its oil outlet is connected to the four-wheel drive control clutch 26 through a pipeline; the four-wheel drive clutch control valve is communicatively connected to the cylinder controller 27.

[0081] Example 12

[0082] On the basis of Example 10 or Example 11, in this embodiment, the AMT cylinder control valve group 28 also includes a differential control clutch 29 and a differential clutch control valve, the oil inlet of the differential clutch control valve is connected to the pipeline between the lubrication pump 13 and the power shift device through a pipeline, and its oil outlet is connected to the differential control clutch 29 through a pipeline; the differential clutch control valve is communicatively connected to the cylinder controller 27.

[0083] Embodiment 13

[0084] On the basis of any one of Examples 10 to 12, in this embodiment, the AMT cylinder control valve group 28 also includes a PTO control clutch 31 and a PTO control valve, the oil inlet of the PTO control valve is connected to the pipeline between the lubrication pump 13 and the power shift device through a pipeline, and the oil outlet is connected to the PTO control clutch 31 through a pipeline; the PTO control valve is communicatively connected to the cylinder controller 27.

[0085] Embodiment 14

[0086] On the basis of any one of Examples 10 to 13, in this embodiment, the AMT cylinder control valve group 28 also includes a PTO brake control clutch 32 and a PTO brake control valve, the oil inlet of the PTO brake control valve is connected to the pipeline between the lubrication pump 13 and the power shift device through a pipeline, and its oil outlet is connected to the PTO brake control clutch 32 through a pipeline; the PTO brake control valve is communicatively connected to the cylinder controller 27.

[0087] The oil inlets of the above-mentioned four-wheel drive clutch control valve, differential clutch control valve, PTO control valve and PTO brake control valve can be directly connected to the pipeline between the lubrication pump 13 and the power shift device through pipelines, or they can be first connected to the oil supply pipeline, and the oil inlet end of the oil supply pipeline is connected to the pipeline between the lubrication pump 13 and the power shift device. The latter is preferred to simplify the pipeline.

[0088] In addition, the oil outlets of the four-wheel drive clutch control valve, differential clutch control valve, PTO control valve and PTO brake control valve can be directly connected to the return oil tank through the return oil pipeline, or they can be first connected to the return oil pipeline, and the oil outlet of the return oil pipeline is connected to the return oil tank.

[0089] Embodiment 15

[0090] On the basis of any one of Embodiments 10 to 14, in this embodiment, the AMT cylinder control valve group 28 includes at least one cylinder mechanism, the oil inlet of each cylinder mechanism is connected to the pipeline between the lubrication pump 13 and the power shift device through a pipeline, and its oil return port is connected to the oil tank; the cylinder mechanism is in communication with the cylinder controller 27. During operation, the corresponding parameters are manually input through the cylinder controller 27 in advance, and the cylinder controller 27 controls the action of the cylinder mechanism according to the corresponding parameters; in this process, the oil pressure signal in the cylinder mechanism will be transmitted to the LS pressure control valve 6, and the LS pressure control valve 6 will send the corresponding pressure signal to the LS pressure controller 4, and the LS pressure controller 4 will control the LS pressure control valve 6 to adjust the oil output of the variable plunger pump 12 according to the signal, so as to avoid excessive oil input and save energy consumption.

[0091] Example 16

[0092] On the basis of Example 15, in this embodiment, each cylinder mechanism includes a control cylinder 30 and two cylinder control valves, wherein the oil inlet of one cylinder control valve is connected to the pipeline between the lubrication pump 13 and the power shift device through a pipeline, and the oil outlet is connected to the oil inlet of the control cylinder 30; the oil outlet of the control cylinder 30 is connected to the oil inlet of another cylinder control valve through a pipeline, and the oil outlet of the other cylinder control valve is connected to the return oil tank through a pipeline.

[0093] In addition, the two cylinder control valves are respectively connected to the cylinder controller 27 for communication.

[0094] During operation, corresponding instructions are input to the cylinder controller 27 manually or through a built-in program, and the cylinder controller 27 controls the cylinder control valve according to the corresponding instructions, so that the cylinder control valve controls the cylinder 30 to move.

[0095] In addition to the above method, the oil inlet of one of the cylinder control valves is connected to the above-mentioned oil supply pipeline through a pipeline, and the oil outlet is connected to the oil inlet of the control cylinder 30; the oil outlet of the control cylinder 30 is connected to the oil inlet of another cylinder control valve through a pipeline, and the oil outlet of the other cylinder control valve is connected to the oil return pipeline through a pipeline.

[0096] The control oil cylinder 30 can realize gear shifting, and one control oil cylinder 30 controls one gear position, and gears are engaged upwards and gears are disengaged downwards. The number of the control oil cylinder 30 can be one or more as required.

[0097] Embodiment 17

[0098] On the basis of Example 15 or Example 16, preferably, in this embodiment, the number of the cylinder mechanisms is two, and the two cylinder mechanisms are arranged in parallel.

[0099] The above-mentioned corresponding parameters manually input in advance through the cylinder controller 27 refer to which control cylinder 30 and the corresponding two cylinder control valves are operated.

[0100] Embodiment 18

[0101] On the basis of the above-mentioned embodiments, in this embodiment, the load sensing port on the steering device is connected to the steering priority valve 3 through a pipeline, and a steering pressure sensor 2 is fixedly installed on the pipeline between the two; the load sensing port on the multi-way valve device 16 is connected to a multi-way valve pressure sensor 1, and the steering pressure sensor 2 and the multi-way valve pressure sensor 1 are respectively connected to the LS pressure controller 4. During operation, the actual working pressure of the steering device is detected by the steering pressure sensor 2, and the actual working pressure of the multi-way valve device 16 is detected by the multi-way valve pressure sensor 1. The two respectively send corresponding pressure signals to the LS pressure controller 4, and the LS pressure controller 4 controls the LS pressure control valve 6 to adjust the output flow of the variable piston pump 12 according to the signal, reducing the input of excessive oil and saving energy consumption.

[0102] When the opening of the steering device and the multi-way valve device 16 remains unchanged, when the actual working pressure of the steering device or the actual working pressure of the multi-way valve device 16 increases / decreases, the LS pressure controller 4 controls the oil port pressure value by reducing / increasing the LS pressure control valve 6, increasing / decreasing the output flow of the variable plunger pump 12, ensuring that the difference between the actual working pressure of the steering device or the actual working pressure of the multi-way valve device 16 and the pressure at the oil outlet of the variable plunger pump 12 reaches a constant value, thereby achieving constant speed control. In the constant power control mode, after the output power of the multi-way valve device 16 reaches the constant power control point, when the actual working pressure of the multi-way valve device 16 increases, the LS pressure controller 4 controls the oil port pressure value by increasing the LS pressure control valve 6, reducing the output flow of the variable plunger pump, thereby achieving constant power control of the output power of the multi-way valve device 16.

[0103] Embodiment 19

[0104] On the basis of Example 18, in this embodiment, a variable pump outlet pressure sensor 5 is fixedly installed on the pipeline between the variable piston pump 12 and the steering priority valve 3, and the variable pump outlet pressure sensor 5 is communicatively connected with the LS pressure controller 4. During operation, the variable pump outlet pressure sensor 5 detects the pressure of the oil at the oil outlet of the variable piston pump 12, and sends a corresponding signal to the LS pressure controller 4. The LS pressure controller 4 controls the LS pressure control valve 6 to adjust the amount of oil output by the variable piston pump 12 according to the signal, so as to avoid inputting excessive oil, save energy consumption, and achieve more precise control.

[0105] Embodiment 20

[0106] On the basis of the above-mentioned embodiments, this embodiment further includes a lubricating device, the oil inlet of the lubricating device is connected to the pipeline between the lubricating pump 13 and the power shift device through a lubricating pipeline; the oil outlet of the steering device is connected to the lubricating pipeline through a pipeline. During operation, the oil is sent to the lubricating device through the lubricating pump 13 for lubrication, which further simplifies the pipeline; in addition, part of the oil in the steering device is supplied to the lubricating device through the corresponding pipeline for lubrication, saving resources.

[0107] Embodiment 21

[0108] On the basis of embodiment 20, in this embodiment, a relief valve 34 is fixedly installed on the lubrication pipeline. During operation, the pressure before the valve is maintained by the relief valve 34 to provide control pressure oil to the LS pressure control valve 6, the shift valve 17 and the AMT cylinder control valve group 28.

[0109] Preferably, in this embodiment, a lubrication pump pressure filter 14 is fixedly installed on the pipeline near the oil outlet of the lubrication pump 13, and the lubrication pump pressure filter 14 is used to filter the oil to remove impurities in the oil to ensure the working performance of each device.

[0110] Embodiment 22

[0111] On the basis of Example 21, this embodiment also includes a boost pump 8 and a bypass control valve group 33, the oil inlet of the boost pump 8 is connected to the pipeline between the transmission box 10 and the variable piston pump 12 through a pipeline, its oil outlet 1 is connected to the oil inlet of the variable piston pump 12 through a pipeline, and the oil outlet 2 is connected to the oil inlet of the bypass control valve group 33 through a pipeline, the oil outlet 1 of the bypass control valve group 33 is connected to the position between the overflow valve 34 and the lubrication device corresponding to the lubrication pipeline through a pipeline, and the oil outlet 2 is connected to the pipeline between the boost pump 8 and the bypass control valve group 33 through a pipeline; the oil inlet of the lubrication pump 13 is connected to the pipeline between the boost pump 8 and the transmission box 10 through a pipeline. During operation, the variable plunger pump 12 is supplied with oil by the booster pump 8, so that the oil inlet of the variable plunger pump 12 has sufficient oil, ensuring the oil absorption performance of the variable plunger pump 12 and improving its working efficiency; on the other hand, the lubricating device is replenished with oil by the booster pump 8 to ensure that the lubricating device obtains sufficient lubricating oil. When the variable plunger pump 12 does not output oil, the bypass control valve group 33 can either return part of the oil to the oil inlet of the booster pump 8, or ensure that the pressure at the oil inlet of the variable plunger pump 12 is not greater than the set safety pressure.

[0112] Preferably, in this embodiment, a one-way valve 25 is further included, the pipeline between the boost pump 8 and the oil outlet 1 of the bypass control valve group 33 is the pipeline 1, and the oil outlet 2 of the bypass control valve group 33 is connected to the pipeline 1 through the pipeline 2; the oil inlet of the one-way valve 25 is connected to the pipeline 2 through the pipeline, and its oil outlet is connected to the pipeline between the oil inlet of the boost pump 8 and the transmission box 10 through the pipeline. When the variable plunger pump 12 does not output oil, the one-way valve 25 can not only flow part of the oil back to the oil inlet of the boost pump 8, but also ensure that the pressure at the oil inlet of the variable plunger pump 12 is not greater than the set safety pressure.

[0113] Embodiment 23

[0114] On the basis of Example 22, the above-mentioned bypass control valve group 33 is composed of two one-way valves, the oil inlets of the two one-way valves are connected through a pipeline, and the oil outlet of the boost pump 8 is connected to the pipeline connecting the two one-way valves through a pipeline; the oil outlets of the two one-way valves are respectively connected to the lubrication pipeline and the pipeline between the boost pump 8 and the bypass control valve group 33.

[0115] Based on the above scheme, when a large amount of lubricating fluid is required for the wet clutch 18 to engage, a large amount of oil flow passes through the left one-way valve, thereby ensuring the working performance and service life of the wet clutch 18; when a small amount of lubricating fluid is required for the wet clutch 18 to engage, a small amount of oil flow passes through the left one-way valve, thereby ensuring the working performance and service life of the wet clutch 18; in a low temperature environment, part of the oil will flow through the right one-way valve, thereby increasing the oil suction pressure of the lubrication pump 13 and improving the working efficiency of the lubrication pump 13.

[0116] Embodiment 24

[0117] On the basis of Example 22, in this embodiment, an oil suction pressure switch 9 is fixedly installed at the connection point between the lubrication pump 13 and the pipeline between the booster pump 8 and the transmission box 10. During operation, the transmission box 10 provides oil to the entire hydraulic system, and the pressure of the oil inlet pipeline of the booster pump 8 and the lubrication pump 13 is controlled by the oil suction pressure switch.

[0118] Preferably, the oil suction pressure switch 9 is connected to an alarm for communication. When the pressure inside the transmission box 10 is too high, the oil suction pressure switch 9 sends a signal to the alarm, and the alarm sounds an alarm to promptly remind the staff to perform maintenance or repair.

[0119] Embodiment 25

[0120] On the basis of Example 24, in this embodiment, an oil suction filter 11 is fixedly installed on the pipeline between the transmission box 10 and the oil suction pressure switch 9. During operation, the oil is preliminarily filtered by the oil suction filter 11 to remove most of the impurities in the oil, thereby preventing the impurities from affecting the working performance of various components.

[0121] Embodiment 26

[0122] On the basis of Example 24 or Example 25, in this embodiment, a pressure oil filter 7 is fixedly installed on the pipeline between the boost pump 8 and the bypass control valve group 33. During operation, the oil is further filtered by the pressure oil filter 7 to remove impurities in the oil, thereby further ensuring the working performance of each component.

[0123] Embodiment 27

[0124] On the basis of any one of Embodiments 20 to 26, in this embodiment, the lubrication device includes a lubrication control oil passage 21 and a cooler 22, the inlet of the cooler 22 is connected to the outlet of the lubrication pipeline, and its outlet is connected to the lubrication control oil passage 21 through a pipeline; the oil outlet of the steering device is connected to the pipeline between the lubrication control oil passage 21 and the cooler 22 through a pipeline. During operation, the oil sent by the lubrication pump 13 is cooled by the cooler 22 and then sent to the lubrication control oil passage 21 for lubrication, thereby ensuring the lubrication effect.

[0125] The lubrication control oil passage 21 is an oil passage for supplying oil to components that need lubrication.

[0126] Embodiment 28

[0127] On the basis of Example 27, in this embodiment, the lubrication device further includes a lubrication bypass valve group 20, the inlet of which is connected to the position of the lubrication pipeline near the cooler 22 through a pipeline, and the outlet of which is connected to the pipeline between the cooler 22 and the lubrication control oil channel 21 through a pipeline; a pressure relief port is also provided on the lubrication bypass valve group 20. During operation, the lubrication bypass valve group 20 serves as a backup lubrication route. When the cooler 22 is blocked, the oil enters the lubrication control oil channel 21 through the lubrication bypass valve group 20 to ensure the normal lubrication operation; and when the inlet pressure of the lubrication control oil channel 20 is too high, part of the oil is discharged through the pressure relief port of the lubrication bypass valve group 20 to perform pressure relief processing to ensure the normal pressure inside the system.

[0128] Embodiment 29

[0129] On the basis of Example 28, in this embodiment, the above-mentioned lubrication bypass valve group 20 is composed of two one-way valves, wherein the inlet and outlet of one of the one-way valves are respectively connected to the position of the lubrication pipeline close to the cooler 22 through pipelines, and its outlet is connected to the pipeline between the cooler 22 and the lubrication control oil channel 21 through a pipeline; the inlet of the other one-way valve is connected to the pipeline between one of the one-way valves and the lubrication control oil channel 21 through a pipeline, and its outlet is the above-mentioned pressure relief port, which is connected back to the oil tank.

[0130] Embodiment 30

[0131] On the basis of the above-mentioned embodiments, this embodiment further includes a safety valve 15, the oil inlet of the safety valve 15 is connected to the pipeline between the steering priority valve 3 and the multi-way valve device 16 through a pipeline, the oil outlet of the multi-way valve device 16 is connected to the oil return pipeline, and the oil outlet of the safety valve 15 is connected to the oil return pipeline through a pipeline. During operation, when the pressure of the oil in the corresponding pipeline is less than the set pressure, all the oil enters the multi-way valve device 16; when the pressure of the oil in the corresponding pipeline is greater than the set pressure, a part of the oil enters the multi-way valve device 16 to provide the normal operation of the multi-way valve device 16, and the other part of the oil is returned through the safety valve 15 to avoid excessive pressure in the system, which is safe and reliable.

[0132] In addition, the oil outlet end of the above-mentioned oil return pipeline is connected to the oil return tank.

[0133] It should be noted that the oil of each of the above-mentioned components can be recovered by respectively returning the oil to the oil tank, or directly recovered into the transmission box 10. The latter is preferred to simplify the structure and reduce the cost.

[0134] Embodiment 31

[0135] On the basis of the above embodiments, in this embodiment, the steering device includes a full hydraulic steering gear 36 and a steering oil cylinder 35. The full hydraulic steering gear 36 is connected to the steering wheel in a transmission manner, and its oil inlet is connected to one of the oil outlets of the steering priority valve 3. The oil outlet is connected to the pipeline between the lubrication control oil channel 21 and the cooler 22, and the load sensing port on it is connected to the steering priority valve 3 through the pipeline; in addition, the oil inlet and oil outlet of the steering oil cylinder 35 are respectively connected to the full hydraulic steering gear 36. During operation, the driver turns the steering wheel to make the L / R working oil port of the full hydraulic steering gear 36 output pressure oil, driving the steering oil cylinder 35 to move left / right to achieve the steering of the tractor.

[0136] in addition, Figure 1 The P port shown in the figure is the oil inlet port, the T port is the oil return port, the LS port is the load sensing port, the L port is the left turn working oil port, and the R port is the right turn working oil port.

[0137] Embodiment 32

[0138] On the basis of the above embodiments, in this embodiment, the multi-way valve device 16 is used to connect the actuators, and the number of the actuators connected thereto may be one or more.

[0139] When the number of actuators is one, the oil pressure required for the execution of the actuator is detected by the multi-way valve pressure sensor 1, and the corresponding pressure signal is sent to the LS pressure controller 4. At the same time, the variable pump outlet pressure sensor 5 also sends the pressure signal to the LS pressure controller 4. The LS pressure controller 4 controls the LS pressure control valve 6 to adjust the oil volume output by the variable plunger pump 12 according to the pressure difference obtained from the two signals, so as to avoid excessive oil input, save energy consumption, and achieve more precise control.

[0140] When there are multiple actuators, there are also multiple multi-way valve pressure sensors 1, which correspond to multiple actuators one by one, and are used to detect the oil pressure required for the operation of multiple actuators, and send the corresponding pressure signal to the LS pressure controller 4. The LS pressure controller 4 determines the maximum oil pressure required for the operation of multiple actuators and the number of actuators working at the same time based on the signal, and obtains the difference between the maximum pressure and the pressure detected by the variable pump outlet pressure sensor 5, and then adjusts the oil output of the variable plunger pump 12 by controlling the control oil port pressure value of the LS pressure control valve 6, avoiding excessive oil input, saving energy consumption, and achieving more precise control. Under the same pressure difference, the more actuators work at the same time, the smaller the control oil port pressure value of the LS pressure control valve 6, and the greater the output flow of the variable plunger pump 12.

[0141] Preferably, in this embodiment, there are four actuators, and the multi-way valve device 16 is provided with four interfaces connected to the four actuators, namely S_1, S_2, S_3 and S_4.

[0142] Embodiment 33

[0143] On the basis of the above embodiments, this embodiment further provides a tractor, including the electro-hydraulic control system as described above. This embodiment provides a tractor with the electro-hydraulic control system, which has the characteristics of fast response speed, high control accuracy, convenient operation, etc., simplifies the hydraulic pipeline; has a constant speed control function, and can switch between high maneuverability and high economy modes; improves the working performance and service life of the wet clutch 18; and has a constant power function, which can ensure that the engine works in the best economic state.

[0144] The operating principle of the present invention is as follows:

[0145] The oil sucked out from the transmission box 10 by the booster pump 8 and passed through the oil suction filter 11 first passes through the oil pressure filter 7, and part of the oil enters the variable plunger pump 12, and the rest of the oil flows into the bypass control valve group 33. The hydraulic oil supplied by the variable plunger pump 12 passes through the steering priority valve 3 and is delivered to the steering device and the multi-way valve device 16 according to different priority levels.

[0146] The oil supplied by the lubrication pump 13 first passes through the lubrication pump pressure filter 14, and outputs the power shift control oil under the action of the relief valve 34. The remaining part merges with the oil flowing out of the bypass control valve group 33 and is transported to the cooler 22 and then merges with the return oil of the full hydraulic steering gear 36. All of them are transported to the lubrication device and finally directly returned to the transmission box 10.

[0147] The LS pressure control valve 6 is used to control the pressure value of the variable control oil port on the variable piston pump 12 to adjust the displacement of the variable piston pump 12.

[0148] System setting parameters: standby LS pressure P1, steering LS pressure P2, LS pressure controller 4 calculates LS pressure PX, PY, adjustable constant speed control pressure difference ΔP, constant power control pressure PP, system maximum working pressure Pmax, the specific operating principle is as follows:

[0149] (1) The tractor hydraulic system is in standby mode, the LS pressure controller 4 controls the output pressure of the LS pressure control valve 6 to be P1, the variable piston pump 12 is in a low flow output state, and the output oil is used for lubrication and leakage of the variable piston pump 12.

[0150] (2) Only the steering device works, with the following two control principles:

[0151] A. The steering pressure sensor 2 transmits the working pressure to the LS pressure controller 4, which outputs a control signal to make the pressure of the oil port of the LS pressure control valve 6 to be P2, and the variable piston pump 12 outputs the constant oil required by the steering system. This control principle ensures that the steering flow is sufficient and safer.

[0152] B. Steering pressure sensor 2 transmits the working pressure signal to LS pressure controller 4, and variable pump outlet pressure sensor 5 sends the pressure signal to LS pressure controller 4. LS pressure controller 4 outputs a control signal based on the pressure difference ΔP3 obtained from the two pressure signals, controls the pressure of the oil port of LS pressure control valve 6, and then adjusts the variable plunger pump 12 to output the oil required by the steering device. The faster / slower the steering device rotates, the more / less the flow rate output by the variable plunger pump 12 will be in order to ensure that the pressure difference ΔP3 is constant. In this control principle, the variable plunger pump 12 provides flow according to the needs of the steering device, and the system is more energy-efficient.

[0153] (3) Only the multi-way valve device 16 works. The driver operates the control knob of the multi-way valve device 16, and the LS pressure controller 4 outputs control signals S_1, S_2, S_3 and S_4. The multi-way valve device 16 performs corresponding actions after receiving the control signals S_1, S_2, S_3 and S_4. The LS pressure controller 4 calculates the difference between the pressure detected by the multi-way valve pressure sensor 1 and the variable pump outlet pressure sensor 5, as well as the number of actuators in real time, and outputs a control signal to control the pressure of the oil port of the LS pressure control valve 6, thereby adjusting the variable piston pump 12 to output the oil required by the multi-way valve device 16. The above-mentioned multi-way valve device 16 is an electronically controlled type. If the multi-way valve device 16 is a manual type, the transmission of the output control signals S_1, S_2, S_3 and S_4 is realized by a mechanical pull rod or a flexible shaft, rather than the LS pressure controller 4.

[0154] (4) The steering device and the multi-way valve device 16 work simultaneously. Assuming that the multi-way valve device 16 is in normal working condition, at this time, the pressure of the LS pressure control valve 6 is PY, the steering device starts to work, and the steering pressure sensor 2 transmits the steering working pressure to the LS pressure controller 4. The LS pressure controller 4 calculates and outputs a control signal corresponding to the total flow required by the steering device and the multi-way valve device 16. If the pressure of the LS pressure control valve 6 is P2+PY, the variable piston pump 12 outputs an oil flow rate that is a constant flow rate required by the steering device + a real-time changing flow rate required by the multi-way valve device 16; if the pressure of the LS pressure control valve 6 is PX+PY, the variable piston pump 12 outputs an oil flow rate that is a real-time changing flow rate required by the steering device + a real-time changing flow rate required by the multi-way valve device 16.

[0155] Assume that the steering device is in normal working condition, at this time the pressure of the LS pressure control valve 6 is PX, the driver operates the control knob of the multi-way valve device 16, the LS pressure controller 4 outputs control signals S_1, S_2, S_3 and S_4, the multi-way valve device 16 receives the control signals S_1, S_2, S_3 and S_4, and performs corresponding actions, the LS pressure controller 4 calculates in real time the difference in pressure detected by the multi-way valve pressure sensor 1 and the variable pump outlet pressure sensor 5, as well as the number of actuators, and outputs a control signal to control the pressure of the control oil port of the LS pressure control valve 6 to PX+PY, thereby adjusting the variable piston pump 12 to output the oil flow required by the steering device and the multi-way valve device 16. (5) The multi-way valve device 16 works in a single connection (with only one actuator). When the load increases / hour, the pressure difference ΔP1 sent back by the multi-way valve pressure sensor 1 and the variable pump outlet pressure sensor 5 is smaller / larger than the constant speed control pressure difference ΔP set by the system. The LS pressure controller 4 calculates and outputs the control signal of the LS pressure control valve 6 according to the absolute value of the difference between ΔP1 and ΔP, thereby achieving the purpose of constant speed control.

[0156] When the constant power control switch of the variable piston pump 12 is turned on and the working pressure reaches the constant power control pressure PP, when the output pressure of the variable piston pump 12 continues to increase, the LS pressure control valve 6 controls the pressure to increase, thereby reducing the output flow of the variable piston pump 12. Conversely, the LS pressure control valve 6 controls the pressure to decrease, thereby increasing the output flow of the variable piston pump 12.

[0157] (6) The multi-way valve device 16 works in multiple connections (multiple actuators work simultaneously). When the maximum load increases, the pressure difference ΔP2 sent back by the multi-way valve pressure sensor 1 and the variable pump outlet pressure sensor 5 is smaller than the constant speed control pressure difference ΔP set by the system. Or, when the maximum load decreases, the pressure difference ΔP2 sent back by the multi-way valve pressure sensor 1 and the variable pump outlet pressure sensor 5 is larger than the constant speed control pressure difference ΔP set by the system. The LS pressure controller 4 calculates and outputs the LS pressure control valve 6 control signal based on the absolute value of the difference between ΔP2 and ΔP, thereby achieving a multi-connected compound action.

[0158] When the total flow required by the multi-way valve device 16 reaches the maximum value that the variable piston pump 12 can provide to the multi-way valve device 16, each actuator of the multi-way valve device 16 distributes all oil flows in proportion according to the size of the opening area. If the working pressure value of the multi-way valve device 16 reaches the maximum working pressure Pmax of the system, the LS pressure controller 4 controls the LS pressure control valve 6 to control the pressure to the maximum, so that the variable piston pump 12 reaches the minimum displacement.

[0159] (7) The constant speed control differential pressure ΔP set by the system can be adjusted according to the speed regulation performance requirements of the multi-way valve device 16. When the constant speed control differential pressure ΔP is small, the speed regulation performance is weak and the power loss is small. On the contrary, the speed regulation performance is good and the power loss is large.

[0160] It should be noted that the above-mentioned electronic components and the corresponding controllers may be connected via wireless communication or via lines.

[0161] In addition, all electronic components involved in the present invention adopt the existing technology, and the above-mentioned components are electrically connected, and the control circuits between the components are the existing technology.

[0162] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An electro-hydraulic control system, characterized in that: The invention comprises a steering device, a multi-way valve device (16), a variable piston pump (12) and a steering priority valve (3), wherein an oil outlet of the variable piston pump (12) is connected to an oil inlet of the steering priority valve (3) through a pipeline, and two oil outlets of the steering priority valve (3) are respectively connected to an oil inlet of the steering device and an oil inlet of the multi-way valve device (16) through pipelines; the invention also comprises a lubrication pump (13), a power shift device and a transmission box (10) filled with oil, wherein the oil inlet of the variable piston pump (12) is connected to the transmission box (10) through a pipeline; the oil inlet of the lubrication pump (13) is connected to a pipeline between the transmission box (10) and the variable piston pump (12) through a pipeline, and the oil outlet thereof is connected to an oil inlet of the power shift device through a pipeline; It also includes a cylinder control device, the oil inlet of which is connected to the power unit through a pipeline. The gear shift device and the lubrication pump (13) are connected by a pipeline; the gear shift device also includes an LS pressure controller (4) and an LS pressure control valve (6); the control oil port of the LS pressure control valve (6) is connected to the second oil outlet of the variable piston pump (12) through a pipeline, and the oil inlet of the LS pressure control valve (6) is connected to the pipeline between the lubrication pump (13) and the power gear shift device through a pipeline; the LS pressure control valve (6), the steering device and the multi-way valve device (16) are respectively connected to the LS pressure controller (4); The oil cylinder control device comprises an AMT oil cylinder control valve group (28) and an accumulator (23). The oil inlet of the AMT oil cylinder control valve group (28) is connected to the pipeline between the lubrication pump (13) and the power shift device through an energy storage pipeline; and the accumulator (23) is connected to the energy storage pipeline through a pipeline.

2. The electro-hydraulic control system according to claim 1, characterized in that: The power shifting device comprises at least one shifting mechanism, and the oil inlet of each shifting mechanism is connected to the oil outlet of the lubrication pump (13) through a pipeline.

3. The electro-hydraulic control system according to claim 2, characterized in that: The power shift device further comprises a power shift controller (19), each of the shift mechanisms comprises a shift valve (17) and a wet clutch (18), the oil inlet of each shift valve (17) being connected to the oil outlet of the lubrication pump (13) via a pipeline, and the control oil port thereof being connected to the corresponding wet clutch (18) via a pipeline; each of the shift valves (17) is respectively connected to the power shift controller (19) in communication.

4. The electro-hydraulic control system according to claim 1, characterized in that: The oil cylinder control device further comprises an oil cylinder controller (27), and the AMT oil cylinder control valve group (28) is communicatively connected to the oil cylinder controller (27).

5. The electro-hydraulic control system according to claim 4, characterized in that: The AMT cylinder control valve group (28) includes at least one clutch control valve and at least one control clutch corresponding to the clutch control valve. The oil inlet of each clutch control valve is connected to the pipeline between the lubrication pump (13) and the power shift device through a pipeline, and the oil outlet is connected to the corresponding control clutch through a pipeline. Each clutch control valve is respectively connected to the cylinder controller (27) for communication.

6. The electro-hydraulic control system according to claim 4, characterized in that: The AMT cylinder control valve group (28) comprises at least one cylinder mechanism, the oil inlet of each cylinder mechanism being connected to a pipeline between the lubrication pump (13) and the power shift device via a pipeline, and being communicatively connected to the cylinder controller (27).

7. The electro-hydraulic control system according to claim 1, characterized in that: The load sensing port on the steering device is connected to the steering priority valve (3) through a pipeline, and a steering pressure sensor (2) is fixedly installed on the pipeline between the two; the load sensing port on the multi-way valve device (16) is connected to a multi-way valve pressure sensor (1), and the steering pressure sensor (2) and the multi-way valve pressure sensor (1) are respectively connected to the LS pressure controller (4) for communication.

8. The electro-hydraulic control system according to claim 7, characterized in that: A variable pump outlet pressure sensor (5) is fixedly installed on the pipeline between the variable piston pump (12) and the steering priority valve (3), and the variable pump outlet pressure sensor (5) is communicatively connected to the LS pressure controller (4).

9. The electro-hydraulic control system according to claim 1, characterized in that: It also includes a lubrication device, the oil inlet of the lubrication device is connected to the pipeline between the lubrication pump (13) and the power shift device through a lubrication pipeline; the oil outlet of the steering device is connected to the lubrication pipeline through a pipeline.

10. The electro-hydraulic control system according to claim 9, characterized in that: An overflow valve (34) is fixedly installed on the lubrication pipeline.

11. The electro-hydraulic control system according to claim 10, characterized in that: It also includes a booster pump (8) and a bypass control valve group (33), wherein the oil inlet of the booster pump (8) is connected to the pipeline between the transmission box (10) and the variable piston pump (12) through a pipeline, the first oil outlet of the booster pump (8) is connected to the oil inlet of the variable piston pump (12) through a pipeline, the second oil outlet is connected to the oil inlet of the bypass control valve group (33) through a pipeline, the first oil outlet of the bypass control valve group (33) is connected to the position of the lubrication pipeline corresponding to the overflow valve (34) and the lubrication device through a pipeline, and the second oil outlet is connected to the pipeline between the booster pump (8) and the bypass control valve group (33) through a pipeline; the oil inlet of the lubrication pump (13) is connected to the pipeline between the booster pump (8) and the transmission box (10) through a pipeline.

12. The electro-hydraulic control system according to claim 11, characterized in that: An oil suction pressure switch (9) is fixedly installed at the connection point of the pipeline between the lubrication pump (13), the booster pump (8) and the transmission box (10).

13. The electro-hydraulic control system according to claim 9, characterized in that: The lubrication device comprises a lubrication control oil passage (21) and a cooler (22); the inlet of the cooler (22) is connected to the outlet of the lubrication pipeline, and the outlet is connected to the lubrication control oil passage (21) via a pipeline; the oil outlet of the steering device is connected to the pipeline between the lubrication control oil passage (21) and the cooler (22) via a pipeline.

14. The electro-hydraulic control system according to claim 13, characterized in that: The lubrication device further comprises a lubrication bypass valve group (20), the inlet of the lubrication bypass valve group (20) being connected to a position of the lubrication pipeline close to the cooler (22) through a pipeline, and the outlet of the lubrication bypass valve group (20) being connected to a pipeline between the cooler (22) and the lubrication control oil channel (21) through a pipeline; the lubrication bypass valve group (20) is also provided with a pressure relief port.

15. The electro-hydraulic control system according to claim 1, characterized in that: It also comprises a safety valve (15), the oil inlet of the safety valve (15) being connected to the pipeline between the steering priority valve (3) and the multi-way valve device (16) through a pipeline, the oil outlet of the multi-way valve device (16) being connected to the oil return pipeline, and the oil outlet of the safety valve (15) being connected to the oil return pipeline through a pipeline.

16. A tractor, characterized in that: Comprising an electro-hydraulic control system as described in any one of claims 1-15.

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