Low-pressure control valve group, electro-hydraulic control system and tractor

Abstract

The present invention discloses a low-pressure control valve group, an electro-hydraulic control system, and a tractor, relating to the field of power shift technology. The low-pressure control valve group includes an oil inlet line, an oil return line, and a first solenoid valve group, a second solenoid valve group, a third solenoid valve group, a first solenoid valve, and a second solenoid valve connected between the oil inlet line and the oil return line. The first solenoid valve group is connected to the AMT cylinder module, the second solenoid valve group is connected to the rear power output shaft, the third solenoid valve group is connected to the clutch group for controlling the gear position, the first solenoid valve is connected to the clutch for controlling the four-wheel drive, and the second solenoid valve is connected to the differential. The low-pressure control valve group provided by the present invention is suitable for functional control of the electro-hydraulic control system in a power shift tractor, achieving a high degree of integration of the low-pressure control valve group. The compact valve body design reduces installation space, makes piping layout more convenient, and effectively reduces costs.

Description

Technical Field

[0001] The present invention relates to the technical field of power shifting, in particular to a low-pressure control valve group, an electro-hydraulic control system and a tractor. Background Art

[0002] Powershift tractors, a trending development in tractors, have become a core technology and have seen rapid growth in China in recent years. Powershift technology utilizes an electro-hydraulic control system to achieve transmission gear changes while maintaining uninterrupted power. The electro-hydraulic control system is key to this technology. The low-pressure control system is a key component of the electro-hydraulic control system within powershift technology. It controls the engagement and braking of the rear PTO, the front and rear differentials, four-wheel drive, the AMT cylinder, and the disengagement and engagement of the wet clutch.

[0003] However, the existing low-pressure system control method is to use four separate valve blocks to control different functions respectively. The installation space of the four valve blocks is large and the piping is relatively complicated. It is inconvenient to arrange the valve blocks for tractors with relatively small space, and the cost of four separate control valve blocks is high. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a low-pressure control valve group, an electro-hydraulic control system and a tractor in view of the deficiencies in the prior art.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A low-pressure control valve group includes: an oil inlet pipeline, an oil return pipeline, and a first solenoid valve group, a second solenoid valve group, a third solenoid valve group, a first solenoid valve, and a second solenoid valve connected between the oil inlet pipeline and the oil return pipeline, wherein the first solenoid valve group is connected to the AMT cylinder module, the second solenoid valve group is connected to the rear power output shaft, the third solenoid valve group is connected to the clutch group for controlling the gear position, the first solenoid valve is connected to the clutch for controlling the four-wheel drive, and the second solenoid valve is connected to the differential.

[0007] Another technical solution of the present invention to solve the above technical problems is as follows:

[0008] An electro-hydraulic control system includes the low-pressure control valve group as described in the above technical solution.

[0009] Another technical solution of the present invention to solve the above technical problems is as follows:

[0010] A tractor comprises the electro-hydraulic control system as described in the above technical solution.

[0011] The beneficial effects of the present invention are as follows: the low-pressure control valve group provided by the present invention is suitable for functional control of the electro-hydraulic control system in a power-shift tractor. By connecting multiple solenoid valve groups with loop pipelines and respectively connecting to control different functions of the electro-hydraulic control system, a high degree of integration of the low-pressure control valve group is achieved. The compact valve body design makes the installation space smaller, the pipeline layout more convenient, and the cost is effectively reduced.

[0012] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of the structural framework of an embodiment of the low-pressure control valve group of the present invention;

[0014] Figure 2 This is a structural schematic diagram of another embodiment of the low-pressure control valve group of the present invention. DETAILED DESCRIPTION

[0015] The principles and features of the present invention are described below with reference to the accompanying drawings. The embodiments given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0016] like Figure 1 As shown, it is a schematic diagram of the structural framework provided by an embodiment of the low-pressure control valve group of the present invention, and the low-pressure control valve group includes: an oil inlet pipeline 100, an oil return pipeline 200, and a first solenoid valve group 10, a second solenoid valve group 20, a third solenoid valve group 30, a first solenoid valve 40 and a second solenoid valve 50 connected between the oil inlet pipeline 100 and the oil return pipeline 200, wherein the first solenoid valve group 10 is connected to the AMT cylinder module, the second solenoid valve group 20 is connected to the rear power output shaft, the third solenoid valve group 30 is connected to the clutch group for controlling the gear, the first solenoid valve 40 is connected to the clutch for controlling the four-wheel drive, and the second solenoid valve 50 is connected to the differential.

[0017] It should be noted that each solenoid valve group can include at least one solenoid valve. The type of solenoid valve can be determined according to the connected functional module. For example, it can include a proportional solenoid valve and a switch solenoid valve. The oil inlet of each solenoid valve is connected to the oil inlet pipeline 100, one oil outlet is connected to the oil return pipeline 200, and the other oil outlet is connected to a different functional module. In this way, after the oil enters the low-pressure control valve group through the oil inlet pipeline 100, the working status of different solenoid valves can be controlled according to actual needs, so that the oil flows in different solenoid valves through the return oil pipeline 200, thereby realizing a high degree of integration of the low-pressure control valve group.

[0018] For example, taking the first solenoid valve 40 as an example, it can be a two-position three-way switch solenoid valve, the oil inlet is connected to the oil inlet pipeline 100, and the low-pressure oil enters the two-position three-way switch solenoid valve through the oil inlet pipeline 100. When the two-position three-way switch solenoid valve is energized, the oil is controlled to enter the clutch in the gearbox that controls the tractor's four-wheel drive, and the clutch is pushed to engage through the piston, thereby switching the tractor to the four-wheel drive working condition. When the two-position three-way switch solenoid valve loses power, the two-position three-way switch solenoid valve is reset, and the oil enters the return oil pipeline 200, stopping the oil supply to the clutch in the gearbox that controls the tractor's four-wheel drive, and the tractor ends the four-wheel drive working condition.

[0019] The control of the remaining functional modules is similar and will not be elaborated here. Since different functional modules may require multiple solenoid valves to be controlled together, such as different gears, the number of solenoid valves in each solenoid valve group can be set according to actual needs.

[0020] It should be understood that, using the solenoid valve as an example to implement the control function, the oil inlet of each solenoid valve can be connected to the oil inlet pipeline 100, and one of the oil outlets can be connected to the oil return pipeline 200. The oil return pipeline 200 is connected only to each solenoid valve, and the other oil outlets can be connected to the oil inlet of the corresponding control module to achieve the control function. The control end of the solenoid valve can be connected to the vehicle control system, receive control signals, and control the power on and off of each solenoid valve based on the control signals.

[0021] For example, assuming that the tractor needs to use the differential when working, the tractor's electronic control system sends an instruction to the controller to supply power to the second solenoid valve 50. The controller supplies power to the second solenoid valve 50 according to the instruction. After the second solenoid valve 50 is energized, it controls the oil to flow into the differential, causing the differential to start working.

[0022] The low-pressure control valve group provided in this embodiment is suitable for functional control of the electro-hydraulic control system in a power-shift tractor. By connecting multiple solenoid valve groups with loop pipelines and respectively controlling different functions of the electro-hydraulic control system, a high degree of integration of the low-pressure control valve group is achieved. The compact valve body design makes the installation space smaller, the pipeline layout more convenient, and the cost is effectively reduced.

[0023] like Figure 2 As shown in the figure, it is a structural diagram of another embodiment of the low-pressure control valve group of the present invention. In the figure, P represents the oil inlet of the oil inlet pipeline, and T represents the oil return port of the oil inlet pipeline. Figure 2 , some optional implementation methods of the present invention are described.

[0024] Optionally, in some possible implementations, the first solenoid valve group 10 includes: a first two-position three-way switch solenoid valve 11, a second two-position three-way switch solenoid valve 12, a third two-position three-way switch solenoid valve 13, and a fourth two-position three-way switch solenoid valve 14, wherein:

[0025] The oil inlet of the first two-position three-way switch solenoid valve 11, the oil inlet of the second two-position three-way switch solenoid valve 12, the oil inlet of the third two-position three-way switch solenoid valve 13, and the oil inlet of the fourth two-position three-way switch solenoid valve 14 are respectively connected to the oil inlet pipeline 100, and the first oil outlet of the first two-position three-way switch solenoid valve 11, the first oil outlet of the second two-position three-way switch solenoid valve 12, the first oil outlet of the third two-position three-way switch solenoid valve 13, and the first oil outlet of the fourth two-position three-way switch solenoid valve 14 are respectively connected to the oil return pipeline 200;

[0026] The second oil outlet of the first two-position three-way switching solenoid valve 11 is connected to the rodless chamber of the first AMT cylinder, the second oil outlet of the second two-position three-way switching solenoid valve 12 is connected to the rodless chamber of the second AMT cylinder, the second oil outlet of the third two-position three-way switching solenoid valve 13 is connected to the rodless chamber of the third AMT cylinder, and the second oil outlet of the fourth two-position three-way switching solenoid valve 14 is connected to the rodless chamber of the fourth AMT cylinder.

[0027] It should be noted that conventional tractors are equipped with only one AMT cylinder, which, due to cost and wiring considerations, typically only provides power output for one gear. Consequently, existing tractors have limited gear selection. However, the present invention, based on a low-pressure control valve group, achieves the ability to control four different AMT cylinders using solenoid valves within a small space, enabling four gear shifts and simplifying wiring layout. Figure 2 In the diagram, TH, TL, TN and TM represent the pressure measuring ports of the AMT cylinder.

[0028] The working process of the first solenoid valve group 10 is described below.

[0029] When the first two-position three-way switch solenoid valve 11 is energized, low-pressure control hydraulic oil enters the rodless chamber of the first AMT oil cylinder, the piston rod extends, drives the shift fork to move, and engages with the synchronizer connected to the shift fork, and the tractor shifts to H gear, which can be a high gear;

[0030] The second two-position three-way switch solenoid valve 12 is energized, and low-pressure control hydraulic oil enters the rodless chamber of the second AMT oil cylinder. The piston rod extends, driving the shift fork to move, and engaging with the synchronizer connected to the shift fork, the tractor shifts to L gear, which can be a medium or low gear.

[0031] When the third two-position three-way switch solenoid valve 13 is energized, low-pressure control hydraulic oil enters the rodless chamber of the third AMT oil cylinder, and the piston rod extends, driving the shift fork to move and engage with the synchronizer connected to the shift fork, and the tractor shifts to N gear, which can be a low gear.

[0032] The fourth two-position three-way switch solenoid valve 14 is energized, and the low-pressure controlled hydraulic oil enters the rodless chamber of the fourth AMT cylinder. The piston rod extends, driving the shift fork to move, and combines with the synchronizer connected to the shift fork, and the tractor switches to M gear, which can be a medium or high gear.

[0033] It should be understood that different gears are determined by the sizes of different gears of the synchronizer. The structure of the synchronizer is common knowledge in the art and will not be described in detail here.

[0034] It should be understood that the principle of solenoid valve controlling the AMT cylinder is common knowledge in the field and will not be elaborated here.

[0035] By setting up four two-position three-way switch solenoid valves to control the four AMT cylinders respectively, combined with the low-pressure control valve group provided by the present invention, the four-stage shifting of the AMT cylinder, namely high, medium-high, medium-low, and low, can be achieved with minimal space occupancy, thereby cooperating with the clutch to achieve multi-stage shifting, which can increase the number of gear shifting levels of the tractor. Moreover, since the low-pressure control valve group provided in this embodiment is highly integrated, it occupies less space and is easy to implement in the tractor.

[0036] Optionally, in some possible implementations, the second solenoid valve group 20 includes: a two-position four-way switch solenoid valve 21 and a first two-position three-way proportional solenoid valve 22, wherein:

[0037] The oil inlet of the first two-position three-way proportional solenoid valve 22 is connected to the oil inlet pipeline 100, the first oil outlet of the first two-position three-way proportional solenoid valve 22 is connected to the oil return pipeline 200, and the second oil outlet of the first two-position three-way proportional solenoid valve 22 is connected to the oil inlet of the two-position four-way switching solenoid valve 21;

[0038] The first oil outlet of the two-position four-way switch solenoid valve 21 is connected to the oil return pipeline 200, and the second oil outlet and the third oil outlet of the two-position four-way switch solenoid valve 21 are connected to the rear power output shaft.

[0039] Figure 2 In the diagram, PTO and PTOB indicate the two oil inlets of the rear power take-off shaft, and TPTO and TPTOB indicate the pressure measuring ports of the rear power take-off shaft.

[0040] The working process of the second solenoid valve group 20 is described below.

[0041] The two-position four-way switch solenoid valve 21 and the first two-position three-way proportional solenoid valve 22 jointly control the rear power output shaft. When the two-position four-way switch solenoid valve 21 loses power and the first two-position three-way proportional solenoid valve 22 is energized, the rear power output shaft starts to output power; when the two-position four-way switch solenoid valve 21 and the first two-position three-way proportional solenoid valve 22 lose power at the same time, the rear power output shaft stops outputting power; when the two-position four-way switch solenoid valve 21 and the first two-position three-way proportional solenoid valve 22 are energized at the same time, the rear power output shaft is braked.

[0042] It should be understood that the principle of the solenoid valve controlling the rear power output shaft is common knowledge in the art and will not be elaborated here.

[0043] The rear power output shaft is controlled jointly by the two-position four-way switching solenoid valve 21 and the first two-position three-way proportional solenoid valve 22, so that the power output, stopping and braking of the rear power output shaft can be achieved with a minimum number of solenoid valves, further reducing space occupancy and cost.

[0044] Optionally, in some possible implementations, the third solenoid valve group 30 includes: a second two-position three-way proportional solenoid valve 31, a third two-position three-way proportional solenoid valve 32, a fourth two-position three-way proportional solenoid valve 33, a fifth two-position three-way proportional solenoid valve 34, a sixth two-position three-way proportional solenoid valve 35, and a seventh two-position three-way proportional solenoid valve 36, wherein:

[0045] The oil inlet of the second two-position three-way proportional solenoid valve 31, the oil inlet of the third two-position three-way proportional solenoid valve 32, the oil inlet of the fourth two-position three-way proportional solenoid valve 33, the oil inlet of the fifth two-position three-way proportional solenoid valve 34, the oil inlet of the sixth two-position three-way proportional solenoid valve 35 and the oil inlet of the seventh two-position three-way proportional solenoid valve 36 are respectively connected to the oil inlet pipeline 100, and the first oil outlet of the second two-position three-way proportional solenoid valve 31, the first oil outlet of the third two-position three-way proportional solenoid valve 32, the first oil outlet of the fourth two-position three-way proportional solenoid valve 33, the first oil outlet of the fifth two-position three-way proportional solenoid valve 34, the first oil outlet of the sixth two-position three-way proportional solenoid valve 35 and the first oil outlet of the seventh two-position three-way proportional solenoid valve 36 are respectively connected to the oil return pipeline 200;

[0046] The second oil outlet of the second two-position three-way proportional solenoid valve 31 is connected to the first clutch in the clutch group, the second oil outlet of the third two-position three-way proportional solenoid valve 32 is connected to the second clutch in the clutch group, the second oil outlet of the fourth two-position three-way proportional solenoid valve 33 is connected to the third clutch in the clutch group, the second oil outlet of the fifth two-position three-way proportional solenoid valve 34 is connected to the fourth clutch in the clutch group, the second oil outlet of the sixth two-position three-way proportional solenoid valve 35 is connected to the fifth clutch in the clutch group, and the second oil outlet of the seventh two-position three-way proportional solenoid valve 36 is connected to the sixth clutch in the clutch group.

[0047] Figure 2 In the diagram, A, B, C, D, E and F represent the oil inlet of each clutch, and TA, TB, TC, TD, TE and TF represent the pressure measuring port of each clutch.

[0048] The working process of the third solenoid valve group 30 is described below.

[0049] It should be noted that the clutch group is set in the gearbox, among which three clutches can be set on one drive shaft of the gearbox, and the remaining three clutches can be set on another drive shaft of the gearbox. One clutch can control the reverse of the vehicle, and the remaining five clutches can control the forward movement of the vehicle. Every two solenoid valves can cooperate with each other to combine the clutches on the two drive shafts, thereby realizing different gear control.

[0050] For ease of explanation, the reverse gear is not considered below, and only the forward gear is considered to explain the control of different gears. Excluding the clutch that controls reverse, the two clutches on one drive shaft and the three clutches on the other drive shaft are combined to achieve a total of 6 gears, which are explained in detail below.

[0051] Assume that the first, second, and third clutches are located on the first transmission shaft, the fourth, fifth, and sixth clutches are located on the second transmission shaft, and the first clutch is in reverse gear, then:

[0052] The third two-position three-way proportional solenoid valve 32 and the fifth two-position three-way proportional solenoid valve 34 are energized simultaneously, and low-pressure control hydraulic oil enters the second clutch piston on the first transmission shaft and the fourth clutch piston on the second transmission shaft respectively. Under the push of the pistons, the two clutches are engaged respectively, and the tractor drives in forward first gear;

[0053] The third two-position three-way proportional solenoid valve 32 and the sixth two-position three-way proportional solenoid valve 35 are energized at the same time, and low-pressure control hydraulic oil enters the second clutch piston on the first transmission shaft and the fifth clutch piston on the second transmission shaft respectively. Under the push of the pistons, the two clutches are engaged respectively, and the tractor drives in forward second gear;

[0054] The third two-position three-way proportional solenoid valve 32 and the seventh two-position three-way proportional solenoid valve 36 are energized at the same time, and low-pressure control hydraulic oil enters the second clutch piston on the first transmission shaft and the sixth clutch piston on the second transmission shaft respectively. Under the push of the pistons, the two clutches are engaged respectively, and the tractor drives in forward gear 3;

[0055] The fourth two-position three-way proportional solenoid valve 33 and the fifth two-position three-way proportional solenoid valve 34 are energized at the same time, and low-pressure control hydraulic oil enters the third clutch piston on the first transmission shaft and the fourth clutch piston on the second transmission shaft respectively. Under the push of the pistons, the two clutches are engaged respectively, and the tractor drives in forward gear 4;

[0056] The fourth two-position three-way proportional solenoid valve 33 and the sixth two-position three-way proportional solenoid valve 35 are energized simultaneously, and low-pressure control hydraulic oil enters the third clutch piston on the first transmission shaft and the fifth clutch piston on the second transmission shaft respectively. Driven by the pistons, the two clutches are engaged, and the tractor drives in forward gear 5;

[0057] The fourth two-position three-way proportional solenoid valve 33 and the seventh two-position three-way proportional solenoid valve 36 are energized at the same time, and the low-pressure control hydraulic oil enters the third clutch piston on the first transmission shaft and the sixth clutch piston on the second transmission shaft respectively. Under the push of the piston, the two clutches are engaged respectively, and the tractor travels in forward 6th gear.

[0058] It should be understood that the principle of solenoid valve controlling the clutch is common knowledge in the art and will not be elaborated here.

[0059] By controlling different clutches through multiple solenoid valves, multi-stage gear shifting of the tractor can be achieved. In addition, the AMT cylinder control synchronizer can also provide 4 gears, namely high gear H gear, medium-high gear M gear, medium-low gear L gear and low gear N gear. Combined with the gear shifting of the clutch group, super-multi-stage gear shifting can be achieved, and 4*6=24 gears can be achieved. Therefore, the method provided in this embodiment can use the least space to provide more gear options for the tractor, which is very suitable for tractors with smaller space. It can not only reduce the space occupation of the electro-hydraulic control system, but also reduce the pipeline layout, reduce the complexity of the electro-hydraulic control system, and reduce costs, thereby solving the problem of the tractor having few gears and will not increase the size of the tractor.

[0060] Optionally, in some possible embodiments, filters 60 are respectively provided at the oil inlet of the first two-position three-way proportional solenoid valve 22, the oil inlet of the second two-position three-way proportional solenoid valve 31, the oil inlet of the third two-position three-way proportional solenoid valve 32, the oil inlet of the fourth two-position three-way proportional solenoid valve 33, the oil inlet of the fifth two-position three-way proportional solenoid valve 34, the oil inlet of the sixth two-position three-way proportional solenoid valve 35 and the oil inlet of the seventh two-position three-way proportional solenoid valve 36.

[0061] It should be noted that the filter 60 can be fixed in the oil circuit to filter impurities in the hydraulic oil, ensure the cleanliness of the hydraulic oil entering the proportional solenoid valve, prevent the proportional solenoid valve core from being stuck, and thus increase the service life of the valve core.

[0062] Optionally, in some possible embodiments, the first solenoid valve 40 includes: a fifth two-position three-way switching solenoid valve 41, the oil inlet of the fifth two-position three-way switching solenoid valve 41 is connected to the oil inlet pipeline 100, the first oil outlet of the fifth two-position three-way switching solenoid valve 41 is connected to the return oil pipeline 200, and the second oil outlet of the fifth two-position three-way switching solenoid valve 41 is connected to the clutch for controlling the four-wheel drive.

[0063] The clutch used to control four-wheel drive is also set in the gearbox, and the oil can push the clutch to engage through the clutch piston.

[0064] Figure 24WD indicates the oil inlet of the clutch used to control the four-wheel drive, and T4WD indicates the pressure measuring port of the clutch used to control the four-wheel drive.

[0065] Next, the operation of the first solenoid valve 40 will be described.

[0066] When the fifth two-position three-way switch solenoid valve 41 is energized, the low-pressure controlled hydraulic oil enters the clutch piston, and the clutch engages under the push of the piston, and the tractor switches to the four-wheel drive working condition; when the fifth two-position three-way switch solenoid valve 41 is de-energized, the low-pressure controlled hydraulic oil stops entering the clutch piston, the piston resets, the clutch disengages, and the tractor ends the four-wheel drive working condition.

[0067] It should be understood that the principle of the solenoid valve controlling the clutch and the principle of the clutch controlling the vehicle's four-wheel drive are common knowledge in the field and will not be elaborated here.

[0068] Optionally, in some possible embodiments, the second solenoid valve 50 includes: a sixth two-position three-way switching solenoid valve 51, the oil inlet of the sixth two-position three-way switching solenoid valve 51 is connected to the oil inlet pipeline 100, the first oil outlet of the sixth two-position three-way switching solenoid valve 51 is connected to the return oil pipeline 200, and the second oil outlet of the fifth two-position three-way switching solenoid valve 41 is connected to the differential.

[0069] Figure 2 DL indicates the oil inlet of the differential, and TDL indicates the pressure measuring port of the differential.

[0070] Next, the operation of the second solenoid valve 50 will be described.

[0071] When the sixth two-position three-way switch solenoid valve 51 is energized, low-pressure control hydraulic oil enters the differential, and the tractor differential starts to work; when the sixth two-position three-way switch solenoid valve 51 is de-energized, the tractor differential stops working.

[0072] It should be understood that the principle of controlling the differential by the solenoid valve is common knowledge in the art and will not be elaborated here.

[0073] Optionally, in some possible implementations, the system further includes: a pressure sensor 70 and an accumulator 80 , and the pressure sensor 70 and the accumulator 80 are in communication with the oil inlet line 100 .

[0074] It should be understood that the pressure sensor 70 is provided with a detection end, which can be directly extended into the oil inlet management to detect the pressure of the oil in the oil inlet pipeline 100. The accumulator 80 has the function of absorbing pressure fluctuations, which can eliminate the pressure fluctuations of the hydraulic oil entering the low-pressure control valve group, ensure the stability of the control pressure, and thus improve the shift control performance.

[0075] Optionally, the pressure sensor 70 and the accumulator 80 may be provided at the inlet of the low-pressure control valve group in the oil inlet line 100 , so as to more accurately monitor and control the oil pressure in the oil inlet line 100 .

[0076] It should be understood that the working principles of the pressure sensor 70 and the accumulator 80 are common knowledge in the art and will not be described in detail here.

[0077] It can be understood that in some embodiments, part or all of the above embodiments may be included.

[0078] The present invention also provides an electro-hydraulic control system, comprising the low-pressure control valve group disclosed in any of the above embodiments.

[0079] It also includes other devices or modules for realizing electro-hydraulic control, for example, it may also include a controller, a gearbox, a rear power output shaft, an AMT cylinder and a differential, etc. The output ports of each solenoid valve in the low-pressure control valve group can be respectively connected to the gearbox, the rear power output shaft, the AMT cylinder and the differential, etc. According to the control of the controller, the corresponding solenoid valve is opened to realize the control of functions such as speed change, gear shifting and differential lock.

[0080] The present invention also provides a tractor comprising the electro-hydraulic control system disclosed in any of the above embodiments.

[0081] It also includes: the vehicle's body and other necessary structures, such as the engine, tires, axles and gears.

[0082] The reader should understand that in the description of this specification, reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0083] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method can be implemented in other ways. For example, the method embodiments described above are merely illustrative. For example, the division of steps is merely a logical function division. In actual implementation, other division methods may be used. For example, multiple steps may be combined or integrated into another step, or some features may be ignored or not performed.

[0084] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A low-pressure control valve group, characterized in that: include: An oil inlet pipeline, an oil return pipeline, and a first solenoid valve group, a second solenoid valve group, a third solenoid valve group, a first solenoid valve, and a second solenoid valve connected between the oil inlet pipeline and the oil return pipeline, wherein the first solenoid valve group is connected to the AMT cylinder module, the second solenoid valve group is connected to the rear power output shaft, the third solenoid valve group is connected to a clutch group for controlling gear positions, the first solenoid valve is connected to a clutch for controlling four-wheel drive, and the second solenoid valve is connected to a differential; The first solenoid valve group includes: a first two-position three-way switch solenoid valve, a second two-position three-way switch solenoid valve, a third two-position three-way switch solenoid valve and a fourth two-position three-way switch solenoid valve, wherein: The oil inlet of the first two-position three-way switch solenoid valve, the oil inlet of the second two-position three-way switch solenoid valve, the oil inlet of the third two-position three-way switch solenoid valve, and the oil inlet of the fourth two-position three-way switch solenoid valve are respectively connected to the oil inlet pipeline, and the first oil outlet of the first two-position three-way switch solenoid valve, the first oil outlet of the second two-position three-way switch solenoid valve, the first oil outlet of the third two-position three-way switch solenoid valve, and the first oil outlet of the fourth two-position three-way switch solenoid valve are respectively connected to the oil return pipeline; The second oil outlet of the first two-position three-way switch solenoid valve is connected to the rodless chamber of the first AMT oil cylinder, the second oil outlet of the second two-position three-way switch solenoid valve is connected to the rodless chamber of the second AMT oil cylinder, the second oil outlet of the third two-position three-way switch solenoid valve is connected to the rodless chamber of the third AMT oil cylinder, and the second oil outlet of the fourth two-position three-way switch solenoid valve is connected to the rodless chamber of the fourth AMT oil cylinder; The second solenoid valve group includes: a two-position four-way switch solenoid valve and a first two-position three-way proportional solenoid valve, wherein: The oil inlet of the first two-position three-way proportional solenoid valve is connected to the oil inlet pipeline, the first oil outlet of the first two-position three-way proportional solenoid valve is connected to the oil return pipeline, and the second oil outlet of the first two-position three-way proportional solenoid valve is connected to the oil inlet of the two-position four-way switching solenoid valve; The first oil outlet of the two-position four-way switch solenoid valve is connected to the oil return pipeline, and the second oil outlet and the third oil outlet of the two-position four-way switch solenoid valve are connected to the rear power output shaft; The third solenoid valve group includes: a second two-position three-way proportional solenoid valve, a third two-position three-way proportional solenoid valve, a fourth two-position three-way proportional solenoid valve, a fifth two-position three-way proportional solenoid valve, a sixth two-position three-way proportional solenoid valve and a seventh two-position three-way proportional solenoid valve, wherein: an oil inlet of the second, two-position, three-way proportional solenoid valve, an oil inlet of the third, two-position, three-way proportional solenoid valve, an oil inlet of the fourth, two-position, three-way proportional solenoid valve, an oil inlet of the fifth, two-position, three-way proportional solenoid valve, an oil inlet of the sixth, two-position, three-way proportional solenoid valve, and an oil inlet of the seventh, two-position, three-way proportional solenoid valve are respectively connected to the oil inlet pipeline, and a first oil outlet of the second, two-position, three-way proportional solenoid valve, a first oil outlet of the third, two-position, three-way proportional solenoid valve, a first oil outlet of the fourth, two-position, three-way proportional solenoid valve, a first oil outlet of the fifth, two-position, three-way proportional solenoid valve, a first oil outlet of the sixth, two-position, three-way proportional solenoid valve, and a first oil outlet of the seventh, two-position, three-way proportional solenoid valve are respectively connected to the oil return pipeline; The second oil outlet of the second two-position three-way proportional solenoid valve is connected to the first clutch in the clutch group, the second oil outlet of the third two-position three-way proportional solenoid valve is connected to the second clutch in the clutch group, the second oil outlet of the fourth two-position three-way proportional solenoid valve is connected to the third clutch in the clutch group, the second oil outlet of the fifth two-position three-way proportional solenoid valve is connected to the fourth clutch in the clutch group, the second oil outlet of the sixth two-position three-way proportional solenoid valve is connected to the fifth clutch in the clutch group, and the second oil outlet of the seventh two-position three-way proportional solenoid valve is connected to the sixth clutch in the clutch group.

2. The low-pressure control valve group according to claim 1, characterized in that: Filters are respectively provided at the oil inlet of the first two-position three-way proportional solenoid valve, the oil inlet of the second two-position three-way proportional solenoid valve, the oil inlet of the third two-position three-way proportional solenoid valve, the oil inlet of the fourth two-position three-way proportional solenoid valve, the oil inlet of the fifth two-position three-way proportional solenoid valve, the oil inlet of the sixth two-position three-way proportional solenoid valve and the oil inlet of the seventh two-position three-way proportional solenoid valve.

3. The low-pressure control valve group according to claim 1, characterized in that: The first solenoid valve includes: a fifth two-position three-way switching solenoid valve, the oil inlet of the fifth two-position three-way switching solenoid valve is connected to the oil inlet pipeline, the first oil outlet of the fifth two-position three-way switching solenoid valve is connected to the return oil pipeline, and the second oil outlet of the fifth two-position three-way switching solenoid valve is connected to the clutch for controlling four-wheel drive.

4. The low-pressure control valve group according to claim 1, characterized in that: The second solenoid valve includes: a sixth two-position three-way switching solenoid valve, the oil inlet of the sixth two-position three-way switching solenoid valve is connected to the oil inlet pipeline, the first oil outlet of the sixth two-position three-way switching solenoid valve is connected to the oil return pipeline, and the second oil outlet of the sixth two-position three-way switching solenoid valve is connected to the differential.

5. The low-pressure control valve assembly according to any one of claims 1 to 4, characterized in that: Also includes: A pressure sensor and an accumulator are connected to the oil inlet pipeline.

6. An electro-hydraulic control system, characterized in that: The low-pressure control valve assembly comprises the low-pressure control valve assembly according to any one of claims 1 to 5.

7. A tractor, characterized in that: Comprising the electro-hydraulic control system as claimed in claim 6.

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