CN112081797A

CN112081797A - Tractor low-voltage electro-hydraulic control system

Info

Publication number: CN112081797A
Application number: CN202011051108.5A
Authority: CN
Inventors: 钟海兵; 程少奇; 索峰
Original assignee: Jiangsu Changfa Agricultural Equipment Co Ltd
Current assignee: Jiangsu Changfa Agricultural Equipment Co Ltd
Priority date: 2020-09-29
Filing date: 2020-09-29
Publication date: 2020-12-15

Abstract

The invention relates to the technical field of tractors, and discloses a low-voltage electro-hydraulic control system of a tractor, which comprises: the oil tank is used as a gearbox shell of the tractor and used for storing oil; the gear pump is connected with the oil tank and used for pumping the oil; the electrohydraulic control valve group is connected with the gear pump, the electrohydraulic control valve group comprises a plurality of electromagnetic valves, liquid inlet ends of the electromagnetic valves are communicated with an oil liquid output end of the gear pump, and output ends of the electromagnetic valves are respectively connected with corresponding execution elements; the liquid inlet end of the emptying reversing valve is communicated with the oil liquid output end of the gear pump, and the liquid outlet end of the emptying reversing valve is connected with a plurality of oil ways. The low-voltage electro-hydraulic control system of the tractor can effectively prevent air from remaining in the hydraulic system, save power consumption, reduce the heating of the system and prolong the service life of a hydraulic element.

Description

Tractor low-voltage electro-hydraulic control system

Technical Field

The invention relates to the technical field of tractors, in particular to a low-voltage electro-hydraulic control system of a tractor.

Background

When the tractor is initially assembled or maintained, no hydraulic oil is in the hydraulic pipeline; when the hydraulic system is placed for a long time, oil at a high position in a pipeline of the hydraulic system flows to a low position due to the influence of self weight, so that air exists in the hydraulic pipeline. When air exists in oil, after the hydraulic system operates, the air in the oil can influence the normal operation of the system, such as the incapability of a hydraulic power assisting device of a clutch and a brake, the combination of a wet clutch and a pause and the like.

Disclosure of Invention

In order to solve the technical problem, the invention provides a low-voltage electro-hydraulic control system of a tractor, which can prevent air from remaining in a hydraulic system, save power consumption, reduce the heat of the system and prolong the service life of a hydraulic element.

The technical scheme provided by the invention is as follows:

a tractor low pressure electro-hydraulic control system comprising:

the oil tank is used as a gearbox shell of the tractor and used for storing oil;

the gear pump is connected with the oil tank and used for pumping the oil;

the electrohydraulic control valve group is connected with the gear pump, the electrohydraulic control valve group comprises a plurality of electromagnetic valves, liquid inlet ends of the electromagnetic valves are communicated with an oil liquid output end of the gear pump, and output ends of the electromagnetic valves are respectively connected with corresponding execution elements;

the liquid inlet end of the emptying reversing valve is communicated with the oil liquid output end of the gear pump, and the liquid outlet end of the emptying reversing valve is connected with a plurality of oil ways.

Among this technical scheme, when the tractor initial assembly, place for a long time or maintenance back, the fluid of eminence can be because of the influence flow direction of dead weight low department in the hydraulic system pipeline, and hydraulic circuit becomes to have the air like this. When air exists in the oil, the air in the oil can influence the normal operation of the system after the hydraulic system operates. Under the effect of evacuation switching-over valve, when the tractor starts, can arrange the air in the system to the greatest extent, guarantee when the system normally works, do not have the air in the hydraulic pressure oil circuit.

Further preferably, the method further comprises the following steps: a system pressure control valve;

the liquid inlet end of the system pressure control valve is communicated with the oil liquid output end of the gear pump, and the liquid outlet end of the system pressure control valve is connected to a plurality of oil ways.

Further preferably, the plurality of electromagnetic valves comprise a power output control valve, a four-wheel drive control valve and a differential lock control valve, and the electro-hydraulic control valve group is provided with a port P, a port PT0, a port 4WD and a port DL;

the port P is used as a liquid inlet of the electro-hydraulic control valve group, a liquid inlet end of the port P is connected with the gear pump, and a liquid outlet end of the port P is respectively connected with liquid inlet ends of the system pressure control valve, the power output control valve, the four-wheel drive control valve, the differential lock control valve and the emptying reversing valve;

the power output control valve is used for being connected with a power output wet clutch through the PT0 port, the four-wheel drive control valve is used for being connected with a four-wheel drive wet clutch through the 4WD port, and the differential lock control valve is used for being connected with a differential lock wet clutch through the DL port.

In the technical scheme, when the power output wet clutch, the four-wheel drive wet clutch and the differential lock wet clutch are not operated, all oil can overflow from a system pressure control valve to a lubricating system or an oil return tank, so that power loss can be caused, the oil is converted into heat energy to cause temperature rise of hydraulic oil, and the oil is deteriorated, so that the service life of elements is shortened. In order to reduce overflow loss, when the power output wet clutch, the four-wheel drive wet clutch and the differential lock wet clutch do not work, the emptying reversing valve is continuously electrified, so that oil is directly communicated to the lubricating system or the oil return tank through the emptying reversing valve, the gear pump runs in a no-load mode, namely, the oil output by the pump flows to the lubricating system or the oil return tank at zero pressure or low pressure, and therefore power consumption can be saved, heating of the system is reduced, and the service life is prolonged.

Further preferably, the oil passage includes a first oil return passage;

the first oil return oil path comprises a lubricating pressure control valve and a T port arranged on the electro-hydraulic control valve group, the liquid inlet end of the lubricating pressure control valve is connected with the system pressure control valve and the emptying reversing valve respectively, and the liquid outlet end of the lubricating pressure control valve is connected with the oil tank through the T port to form a circulation loop.

Further preferably, the oil passage further includes a second power train lubrication oil passage;

the second transmission system lubricating oil path comprises a Lub port and a hydraulic radiator, the Lub port and the hydraulic radiator are arranged on the electro-hydraulic control valve group, the liquid inlet end of the Lub port is connected with the system pressure control valve and the emptying reversing valve respectively, the liquid inlet end of the hydraulic radiator is connected with the liquid outlet end of the Lub port, the liquid outlet end of the hydraulic radiator is connected with a transmission system lubricating damping plug, and the liquid outlet end of the transmission system lubricating damping plug is connected with the oil tank.

In the technical scheme, the hydraulic radiator is a device for cooling oil in a hydraulic system, the oil is subjected to efficient heat exchange with cold air which forcibly flows in a heat exchanger, so that the oil temperature is reduced to the working temperature to ensure that the system can continuously and normally operate, and the work can be smoothly carried out; after being pumped out of an oil tank, oil enters from a port P of the electro-hydraulic control valve group and is preferentially shunted through a right position of the emptying reversing valve, and no matter whether a power output control valve, a four-wheel drive control valve and a differential lock control valve are in a connected state or not, one path of oil comes out of a port Lub of the electro-hydraulic control valve group and is respectively lubricated for a power output wet clutch, a four-wheel drive wet clutch and a differential lock wet clutch through a hydraulic radiator; and the lubricating oil enters the oil tank after lubricating the transmission system by the transmission system lubricating damping plug to form a circulating loop.

Further preferably, the oil path further comprises a third gear pump lubricating oil path;

the third gear pump lubricating oil path comprises a gear pump lubricating throttle valve, an LG port and a gear pump lubricating damping plug, the inlet end of the gear pump lubricating throttle valve is connected with the system pressure control valve and the emptying reversing valve respectively, and the outlet end of the gear pump lubricating throttle valve is connected with the LG port; the gear pump lubrication throttling valve and the LG port are arranged in the electro-hydraulic control valve group, and the LG port is connected with the oil tank through the gear pump lubrication damping plug.

In the technical scheme, after being pumped out of an oil tank, oil enters from a P port of an electro-hydraulic control valve group and is preferentially distributed through a right position of an emptying reversing valve, and no matter whether a power output control valve, a four-wheel drive control valve and a differential lock control valve are in a connected state or not, the oil in one way passes through a gear pump lubricating throttle valve, comes out of an LG port of the electro-hydraulic control valve group, lubricates the gear pump, and then enters the oil tank to form a circulation loop.

Further preferably, a wet clutch lubricating oil path is arranged on the third gear pump lubricating oil path and/or the second transmission system lubricating oil path, and a liquid outlet end of the wet clutch lubricating oil path is respectively communicated to the power output wet clutch, the four-wheel drive wet clutch and the differential lock wet clutch.

Further preferably, the method further comprises the following steps: a power take-off accumulator;

the PT0 port is connected to the power output wet clutch through the power output accumulator, and the power output accumulator is used for playing a buffer role when the power output wet clutch is separated and combined.

In the technical scheme, the power output energy accumulator is an energy accumulator which plays a role in buffering for the separation and combination of the power output wet clutch. When the power output wet clutch is combined and separated, the load connected with the power output can feed back and impact the tractor, and jerk and fluctuation can be caused to a hydraulic system. The power output energy accumulator can absorb and release impact caused by the combination and separation of the power output wet clutch, has a buffering effect on a hydraulic system, and enables the power output to be more stably connected. As an auxiliary power source, the pump power can be reduced, the efficiency is improved, the temperature rise is reduced, the energy is saved, and the energy loss of the system and the heat generation caused by the energy loss are reduced.

Further preferably, the method further comprises the following steps: the clutch boosting system is arranged between the oil output end of the gear pump and the port P and comprises a clutch booster master cylinder and a clutch booster oil distribution cylinder, one end of the clutch booster master cylinder is connected with the liquid outlet end of the pressure oil line oil filter, and the other end of the clutch booster master cylinder is connected with the clutch booster oil distribution cylinder;

and/or the brake power-assisted system is arranged between the pressure oil line oil filter and the port P, the brake power-assisted system comprises a brake booster master cylinder and a brake booster oil distribution cylinder, one end of the brake booster master cylinder is connected with the liquid outlet end of the pressure oil line oil filter, and the other end of the brake booster master cylinder is connected with the brake booster oil distribution cylinder.

Further preferably, the method further comprises the following steps: a boost accumulator;

the boosting accumulator is arranged between the pressure oil filter and the port P and is respectively connected with the clutch booster master cylinder and/or the brake booster master cylinder, and the boosting accumulator is used for providing temporary power for the clutch booster master cylinder and/or the brake booster master cylinder.

In the technical scheme, the boosting accumulator is an accumulator which provides temporary power for the clutch boosting system and the brake boosting system and stores hydraulic power when the tractor runs. When the tractor is not started, the gear pump is replaced to serve as a temporary power source of the clutch power-assisted system and the brake power-assisted system, when the clutch power-assisted system and the brake power-assisted system need to work, transient hydraulic force is provided, and driving and riding control performance and comfort are improved.

Compared with the prior art, the low-voltage electro-hydraulic control system of the tractor has the beneficial effects that:

according to the tractor low-pressure electro-hydraulic control system, when the tractor is started, air in the system can be exhausted through the exhaust reversing valve, and the condition that no air exists in a hydraulic oil way when the system works normally is guaranteed; when the power output wet clutch, the four-wheel drive wet clutch and the differential lock wet clutch do not work, the emptying reversing valve is continuously electrified, so that oil is directly communicated to the lubricating system or the oil return tank through the emptying reversing valve, the gear pump runs in a no-load mode, namely, the oil output by the pump flows to the lubricating system or the oil return tank at zero pressure or low pressure, the power consumption can be saved, the heating of the system is reduced, and the service life is prolonged.

Drawings

The foregoing features, technical features, advantages and embodiments are further described in the following detailed description of the preferred embodiments, which is to be read in connection with the accompanying drawings.

FIG. 1 is a hydraulic schematic diagram of a low-pressure electro-hydraulic control system of a tractor according to the embodiment;

fig. 2 is a hydraulic schematic diagram of the electro-hydraulic control valve group of the embodiment.

The reference numbers illustrate:

1. the hydraulic control system comprises an oil tank, 2 parts of an oil suction oil filter, 3 parts of a gear pump, 4 parts of a pressure oil filter, 5 parts of a power-assisted accumulator, 6 parts of an electro-hydraulic control valve group, 7 parts of a power output accumulator, 8 parts of a power output wet clutch, 9 parts of a four-wheel drive wet clutch, 10 parts of a differential lock wet clutch, 11 parts of a gear pump lubrication damping plug, 12 parts of a transmission system lubrication damping plug, 13 parts of a hydraulic radiator, 14 parts of a clutch booster master cylinder, 15 parts of a clutch booster slave cylinder, 16 parts of a brake booster master cylinder, 17 parts of a brake booster slave cylinder, 18 parts of a system pressure control valve, 19 parts of a power output control valve, 20 parts of a four-wheel drive control valve, 21 parts of a differential lock control valve, 22 parts of an emptying reversing valve, 23 parts of a lubrication pressure control valve, 24 parts of a gear pump lubrication throttling valve, 25 parts of a P port, 26 parts of a T port, 27 parts of a Lub port, 28 parts of an LG port.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

For the sake of simplicity, the drawings only schematically show the parts relevant to the present invention, and they do not represent the actual structure as a product. In addition, in order to make the drawings concise and understandable, components having the same structure or function in some of the drawings are only schematically illustrated or only labeled. In this document, "one" means not only "only one" but also a case of "more than one".

It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

In the embodiments shown in the drawings, the directions such as up, down, left, right, front, and rear are used to explain the structure and movement of various components of the present invention not absolutely but relatively. These illustrations are appropriate when these components are in the positions shown in the figures. If the description of the positions of these components changes, the indication of these directions changes accordingly.

In addition, in the description of the present application, the terms "first", "second", and the like are used only for distinguishing the description, and are not intended to indicate or imply relative importance. In the description of the present application, "a number" means at least one, such as one, two, etc., unless specifically limited otherwise. Furthermore, it is to be understood that the term "coupled" is to be interpreted broadly, unless explicitly stated or limited otherwise. For example, the connection can be fixed, detachable or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, or through the communication between two elements.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will be made with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.

As a specific embodiment, as shown in fig. 1 and fig. 2, the present embodiment provides a low-voltage electro-hydraulic control system for a tractor, including: the device comprises an oil tank 1, a gear pump 3, an electro-hydraulic control valve group 6 and an emptying reversing valve 22. Wherein, the oil tank 1 is used as the tractor gearbox casing for save fluid. The gear pump 3 is connected with the oil tank 1 and used for pumping oil. The electrohydraulic control valve group 6 is connected with the gear pump 3, the electrohydraulic control valve group comprises a plurality of electromagnetic valves, liquid inlet ends of the electromagnetic valves are respectively communicated with an oil liquid output end of the gear pump 3, and output ends of the electromagnetic valves are respectively connected with corresponding executing elements. The liquid inlet end of the emptying reversing valve 22 is communicated with the oil liquid output end of the gear pump 3, and the liquid outlet end of the emptying reversing valve 22 is connected with a plurality of oil ways.

In this embodiment, the evacuation switching valve 22 is a two-position two-way electromagnetic switch valve, and is normally closed in the oil path. The evacuation changeover valve 22 is preferably arranged in the electrohydraulic control valve block 6, so that the integration is higher and the device is more compact. The liquid outlet end of the evacuation reversing valve 22 is connected with an oil way or a plurality of oil ways, when the tractor is started, the evacuation reversing valve 22 is electrified due to a starting instruction, the electromagnetic coil is attracted, the oil way of the evacuation reversing valve 22 is switched to a connection state, and at the moment, oil can circulate in a system pipeline in a hollow load mode to exhaust air. When the air is exhausted, the solenoid of the exhaust directional valve 22 is de-energized, and the oil passage is switched to a closed state, which is the normal operating state of the hydraulic system. When the electromagnetic valves are all in a closed state, in order to reduce overflow loss, the emptying reversing valve 22 is continuously powered, so that oil is directly communicated to a lubricating system or an oil return tank through the emptying reversing valve 22, the gear pump 3 is in no-load operation, namely, all the oil output by the pump flows to the lubricating system or the oil return tank at zero pressure or low pressure, so that the power consumption can be saved, the heating of the system is reduced, and the service life is prolonged.

Further, tractor low pressure electricity liquid control system still includes: a system pressure control valve 18; the liquid inlet end of the system pressure control valve 18 is respectively connected with a plurality of electromagnetic valves in parallel, the liquid outlet end of the system pressure control valve 18 is connected to a plurality of oil ways, and the plurality of electromagnetic valves are preferably switch valves, so that the electromagnetic valves are powered on and powered off, and the combination or separation of the wet clutch is controlled. The electromagnetic valves can be a power output control valve 19, a four-wheel drive control valve 20 and a differential lock control valve 21, and the electro-hydraulic control valve group 6 is provided with a P port 25, a PT0 port 29, a 4WD port 30 and a DL port 31. The P port 25 is used as a liquid inlet of the electro-hydraulic control valve group 6, the liquid inlet end of the P port 25 is connected with the gear pump 3, and the liquid outlet end of the P port 25 is respectively connected with the system pressure control valve 18, the power output control valve 19, the four-wheel drive control valve 20, the differential lock control valve 21 and the emptying reversing valve 22. The liquid inlet end of the system pressure control valve 18 is arranged between the liquid outlet end of the P port 25 and the power output control valve 19, the four-wheel drive control valve 20 and the differential lock control valve 21; the liquid inlet end of the emptying reversing valve 22 is respectively connected with the power output control valve 19, the four-wheel drive control valve 20 and the differential lock control valve 21; the liquid outlet end of the emptying reversing valve 22 and the liquid outlet end of the system pressure control valve 18 are connected with a plurality of oil passages. The power output control valve 19 is connected to the power output wet clutch 8 through a port PT0, the four-wheel drive control valve 20 is connected to the four-wheel drive wet clutch 9 through a port 4WD 30, and the differential lock control valve 21 is connected to the differential lock wet clutch 10 through a port DL 31.

In this embodiment, when the power output wet clutch 8, the four-wheel drive wet clutch 9 and the differential lock wet clutch 10 are not in operation, all the oil will overflow from the system pressure control valve 18 to the lubrication system or the oil return tank, so that power loss will be caused, the oil is converted into heat energy to cause temperature rise of the hydraulic oil, and the oil is deteriorated, so that the service life of the elements is reduced. In order to reduce the overflow loss, when the power output wet clutch 8, the four-wheel drive wet clutch 9 and the differential lock wet clutch 10 do not work, the emptying reversing valve 22 is continuously electrified, so that the oil is directly communicated to the lubricating system or the oil return tank through the emptying reversing valve 22, the gear pump 3 runs in no-load, namely the oil output by the pump flows to the lubricating system or the oil return tank under zero pressure or low pressure, and therefore, the power consumption can be saved, the heat generation of the system is reduced, and the service life is prolonged.

In another embodiment, as shown in fig. 1 and fig. 2, based on the above embodiments, the oil path includes a first oil return path, the first oil return path includes a lubrication pressure control valve 23 and a T port 26 disposed on the electrohydraulic control valve group 6, a liquid inlet end of the lubrication pressure control valve 23 is connected to the system pressure control valve 18 and the drain reversing valve 22, and a liquid outlet end of the lubrication pressure control valve 23 is connected to the oil tank 1 through the T port 26 to form a circulation loop.

Further, the oil circuit further comprises a second transmission system lubricating oil circuit, the second transmission system lubricating oil circuit comprises a Lub port 27 and a hydraulic radiator 13, the Lub port 27 and the hydraulic radiator 13 are arranged on the electro-hydraulic control valve group 6, the liquid inlet end of the hydraulic radiator 13 is connected with the Lub port 27, and the liquid outlet end of the hydraulic radiator 13 is respectively connected with the power output control valve 19, the four-wheel drive control valve 20 and the differential lock control valve 21. The second power train lubrication oil passage further includes: the liquid inlet end of the transmission system lubrication damping plug 12 is connected with the hydraulic radiator 13, and the liquid outlet end of the transmission system lubrication damping plug 12 is connected with the oil tank 1. The hydraulic radiator 13 is a device for cooling oil in a hydraulic system, and the oil is subjected to efficient heat exchange with cold air which forcibly flows in a heat exchanger, so that the oil temperature is reduced to the working temperature to ensure that the system can continuously and normally operate, and the work can be smoothly carried out. One end of a transmission system lubrication damping plug 12 is connected with a hydraulic radiator 13, and the other end of the transmission system lubrication damping plug 12 is connected with the oil tank 1. After being pumped out from the oil tank 1, oil enters from a P port 25 of the electro-hydraulic control valve group 6, preferentially flows through a right shunt of the emptying reversing valve 22, and one path of oil comes out from a Lub port 27 of the electro-hydraulic control valve group 6 and is respectively lubricated for the power output wet clutch 8, the four-wheel drive wet clutch 9 and the differential lock wet clutch 10 through the hydraulic radiator 13 no matter whether the power output control valve 19, the four-wheel drive control valve 20 and the differential lock control valve 21 are in a connection state or not, and enters the oil tank 1 after being lubricated for the transmission system from the transmission system lubricating damping plug 11, so that a circulation loop is formed.

Further, the oil circuit also comprises a third gear pump lubricating oil circuit, the third gear pump lubricating oil circuit comprises a gear pump lubricating throttle valve 24, an LG port 28 and a gear pump lubricating damping plug 11, the inlet end of the gear pump lubricating throttle valve 24 is respectively connected with a system pressure control valve 18 and an emptying reversing valve 22, and the outlet end of the gear pump lubricating throttle valve 24 is connected with the LG port 28; the gear pump lubrication throttle valve 24 and the LG port 28 are arranged in the electro-hydraulic control valve group 6, and the LG port 28 is connected with the oil tank 1 through the gear pump lubrication damping plug 11. After being pumped out from the oil tank 1, oil enters from a P port 25 of the electro-hydraulic control valve group 6 and is preferentially distributed through the right position of the emptying reversing valve 22, and no matter whether the power output control valve 19, the four-wheel drive control valve 20 and the differential lock control valve 21 are in a connected state or not, one path of oil passes through the gear pump lubricating throttle valve 24, exits from an LG port 28 of the electro-hydraulic control valve group 6, lubricates the gear pump 3 and then enters the oil tank to form a circulation loop. The forced lubrication is provided for the transmission mechanism of the transmission system, and the lubrication is provided for the gear pump 3 on the gearbox.

Furthermore, a wet clutch lubricating oil path is arranged on the third gear pump lubricating oil path and/or the second transmission system lubricating oil path, and the liquid outlet end of the wet clutch lubricating oil path is respectively communicated to the power output wet clutch 8, the four-wheel drive wet clutch 9 and the differential lock wet clutch 10.

Preferably, the liquid inlet end of the wet clutch lubricating oil path is connected between the hydraulic radiator 13 and the transmission system lubricating damping plug 12, and the liquid outlet end is respectively communicated to the power output wet clutch 8, the four-wheel drive wet clutch 9 and the differential lock wet clutch 10, so as to provide lubricating action for each wet clutch, ensure that the lubricating oil is cold oil, and improve the lubricating effect on the wet clutch.

In another embodiment, as shown in fig. 1 and fig. 2, on the basis of the above embodiments, the tractor low-pressure electro-hydraulic control system further includes: the power output accumulator 7 and the PT0 port 21 are connected to the power output wet clutch 8 through the power output accumulator 7, and the power output accumulator 7 is used for playing a buffer role when the power output wet clutch 8 is separated and combined. Under the general condition, when the tractor frequently articulates power take off, it is great to hydraulic system impact, causes the damage to power take off wet clutch 8 easily, and the driver also feels when the operation and gets the feeling of setback, reduces and controls and experiences. The power output accumulator 7 is an accumulator that functions as a buffer for the separation and combination of the power output wet clutch 8. When the power output wet clutch 8 is engaged and disengaged, the load connected to the power output will feed back and impact the tractor, and will cause jerking and fluctuation to the hydraulic system. The power output energy accumulator 7 can absorb and release impact caused by the combination and separation of the power output wet clutch 8, and has a buffer effect on a hydraulic system, so that the power output hanging connection is more stable. As an auxiliary power source, the pump power can be reduced, the efficiency is improved, the temperature rise is reduced, the energy is saved, and the energy loss of the system and the heat generation caused by the energy loss are reduced.

Further, as shown in fig. 1, the low-voltage electro-hydraulic control system of the tractor further comprises: oil suction filter and 2 pressure oil filter 4. One end of the oil suction filter 2 is connected with the oil tank 1, the other end of the oil suction filter 2 is connected with the gear pump 3, one end of the pressure oil filter 4 is connected with the gear pump 3, and the other end of the pressure oil filter 4 is connected with the port P25. Through installing oil absorption filter 2 in 3 oil absorption mouths of gear pump for protect gear pump 3 and other hydraulic component, in order to avoid inhaling the contaminated impurity, control hydraulic system pollution effectively, transfer hydraulic system's cleanliness. The pressure oil-way oil filter 4 mainly functions to filter oil, various impurities inevitably appear in a hydraulic system, and the cleanliness of the oil can be further improved through the pressure oil-way oil filter 4.

Further, as shown in fig. 1, the low-voltage electro-hydraulic control system of the tractor further comprises: clutch boosting system, brake boosting system and boosting accumulator 5. The clutch boosting system is arranged between the pressure oil line oil filter 4 and the P port 25 and comprises a clutch booster master cylinder 14 and a clutch booster sub-cylinder 15, one end of the clutch booster master cylinder 14 is connected with the pressure oil line oil filter 4, and the other end of the clutch booster master cylinder 14 is connected with the clutch booster sub-cylinder 15. The brake power assisting system is arranged between the pressure oil line oil filter 4 and the P port 25 and comprises a brake booster master cylinder 16 and a brake booster sub-cylinder 15, one end of the brake booster master cylinder 16 is connected with the pressure oil line oil filter 4, and the other end of the brake booster master cylinder 16 is connected with a brake booster sub-cylinder 17. The boosting energy accumulator 5 is arranged between the pressure oil filter 4 and the P port 25 and is respectively connected with the clutch booster master cylinder 14 and the brake booster master cylinder 16, and the boosting energy accumulator 5 is used for providing temporary power for the clutch booster master cylinder 14 and the brake booster master cylinder 16.

Normally, when the tractor is not started, the clutch power assisting system and the brake power assisting system are hydraulic power-free and cannot play a power assisting role. The boosting accumulator 5 is an accumulator for providing temporary power for the clutch boosting system and the brake boosting system, and stores hydraulic power when the tractor runs. When the tractor is not started, the gear pump 3 is replaced to serve as a temporary power source of the clutch power-assisted system and the brake power-assisted system, when the clutch power-assisted system and the brake power-assisted system need to work, transient hydraulic force is provided, and the driving and riding control performance and the driving comfort are improved.

In this embodiment, under normal operation of the tractor, the power output control valve 19, the four-wheel drive control valve 20 and the differential lock control valve 21 are electrically triggered, and the corresponding oil passages are connected, so as to respectively couple the corresponding power output wet clutch 8, the four-wheel drive wet clutch 9 and the differential lock wet clutch 10, and drive the corresponding mechanisms, so as to operate the power output, the four-wheel drive and the differential lock. When the power output control valve 19, the four-wheel drive control valve 20 and the differential lock control valve 21 are powered off, the corresponding oil passages are closed, the corresponding power output wet clutch 8, the corresponding four-wheel drive wet clutch 9 and the corresponding differential lock wet clutch 10 are separated, the corresponding mechanisms stop operating, and the power output, the four-wheel drive and the differential lock stop operating. The drain switch valve 22 will then be energized, allowing oil to pass directly to the lubrication system or return tank through the drain switch valve 22. When a clutch pedal or a brake pedal is stepped on, the clutch booster master cylinder 14 and the brake booster master cylinder 16 are linked, so that an oil path of a hydraulic power assisting system is communicated, and pressure oil pushes the clutch booster slave cylinder 15 and the brake booster slave cylinder 17, thereby achieving the purpose of hydraulic power assisting. When the clutch or brake pedal is released, the clutch booster master cylinder 14 and the brake booster master cylinder 16 are linked, the oil circuit of the hydraulic power-assisted system is closed, the oil return circuit is opened, and hydraulic oil returns to the oil tank 1 from the clutch booster sub-oil cylinder 15 and the brake booster sub-oil cylinder 17. The drain switch valve 22 will then be energized, allowing oil to pass directly to the lubrication system or return tank through the drain switch valve 22. The wet clutch hydraulic control and hydraulic power assisting device subsystems are independent and do not interfere with each other. When either one of the two valves works, the emptying reversing valve 22 is in a closed state, and when the other one of the two valves does not work, the emptying reversing valve 22 is electrified, so that the aim of reducing power loss is fulfilled.

The booster accumulator 5 is designed on the oil path of the clutch booster master cylinder 14 and the brake booster master cylinder 16, when the tractor is not started, the clutch booster system and the brake booster system are hydraulic power-free and cannot play a boosting role. However, under the action of the pressure stored by the power-assisted energy accumulator 5, the clutch booster master cylinder 14 and the brake booster master cylinder 16 still have transient power sources, and the clutch booster cylinder 15 and the brake booster cylinder 17 still have a boosting effect, so that the driving controllability is improved.

The power output accumulator 7 is designed on the oil path of the power output wet clutch 8. When the tractor normally works, the power output is connected with an agricultural implement, and when the power output is frequently hung, large impact can be caused to a hydraulic system. Under the action of the power output energy accumulator 7, the impact caused by the power output on-load hanging can be absorbed, the buffering effect is achieved, and the power output hanging is more stable.

The emptying reversing valve 22 is designed in the electro-hydraulic control valve group 6, so that air can be prevented from remaining in a hydraulic system, power consumption can be saved, heating of the system is reduced, and the service life of a hydraulic element is prolonged. When the tractor is initially assembled, is placed for a long time or is maintained, the fluid at a high position in the hydraulic system pipeline flows to a low position due to the influence of self weight, so that air exists in the hydraulic pipeline. When the air in the oil liquid is used, the air in the oil liquid can influence the normal operation of the system after the hydraulic system operates. Under the action of the emptying reversing valve 22, when the tractor is started, air in the system can be exhausted, and the condition that no air exists in a hydraulic oil circuit when the system works normally is ensured. When the wet clutch and the hydraulic power assisting device do not work, all oil can overflow from the system pressure control valve 18 in the electro-hydraulic control valve group 6 to a lubricating system or an oil return tank, so that power loss can be caused, the oil is converted into heat energy to cause temperature rise of the hydraulic oil, the oil is deteriorated, and the service life of elements is shortened. In order to reduce overflow loss, when the three wet clutches and the two hydraulic power assisting devices do not work, the emptying reversing valve 22 is continuously electrified, so that oil is directly communicated to a lubricating system or an oil return tank through the emptying reversing valve 22, the gear pump 3 runs in a no-load mode, namely, the oil output by the pump flows to the lubricating system or the oil return tank under zero pressure or low pressure, power consumption can be saved, heating of the system is reduced, and the service life is prolonged.

In this embodiment, the specific oil path route of the tractor low-pressure electro-hydraulic control system is as follows:

emptying an oil path:

when the tractor is initially assembled, placed for a long time or maintained, air exists in the hydraulic pipeline, and when the tractor is started, the hydraulic system needs to exhaust the air. Starting an emptying oil way route: as shown in fig. 1 and 2, each element is in an initial state, when the tractor is started, the evacuation switching valve 22 is energized according to a start command, the electromagnetic coil is closed, and the oil passage is switched to a connected state. Oil enters from a P port 25 of the electro-hydraulic control valve group 6 through the oil tank 1, the oil suction filter 2, the gear pump 3 and the pressure oil filter 4, is preferentially shunted through a right position of the evacuation reversing valve 22, and passes through the gear pump lubrication throttle valve 24 all the way regardless of whether the power output control valve 19, the four-wheel drive control valve 20 and the differential lock control valve 21 are in a connected state or not, and comes out from an LG port 28 of the electro-hydraulic control valve group 6 to lubricate the gear pump 3 and then enters the oil tank 1 to form a circulation loop. The other path of the lubricating oil flows out from a Lub port 27 of the electro-hydraulic control valve group 6 and is respectively lubricated for a power output wet clutch 8, a four-wheel drive wet clutch 9 and a differential lock wet clutch 10 through a hydraulic radiator 13; and the lubricating oil enters the oil tank 1 after lubricating the transmission system from the transmission system lubricating damping plug 12 to form a circulation loop. And the other path controls the lubricating pressure through a lubricating pressure control valve 23 and directly enters the oil tank 1 to form a circulating loop. At the moment, oil can be circulated in a system pipeline in a hollow mode, air is exhausted, and the air cannot enter each wet clutch and each power-assisted oil cylinder. After the air is exhausted, if the power output control valve 19, the four-wheel drive control valve 20, the differential lock control valve 21, the clutch booster master cylinder 14 and the brake booster master cylinder 16 are all in a closed state, the evacuation reversing valve 22 is continuously powered on, and all oil flows to a lubricating system or an oil return tank, so that the purpose of reducing power consumption is achieved. When the air is exhausted, the exhaust diverter valve 22 is de-energized if one of the components is in the on state.

(II) wet clutch working oil path route: as shown in fig. 1 and 2, each element is in an initial state after evacuation is started.

1. Power output control oil circuit route: when the power output control switch is closed, the power output control valve 19 is in a power-off state and the oil passage is in a closed state. Oil enters from a P port 25 of the electro-hydraulic control valve group 6 through the oil tank 1, the oil suction filter 2, the gear pump 3 and the pressure oil filter 4, the evacuation reversing valve 22 is continuously powered after evacuation, the oil is shunted to the right through the evacuation reversing valve 22, passes through the gear pump lubricating throttle valve 24 all the way, comes out from an LG port 28 of the electro-hydraulic control valve group 6, lubricates the gear pump 3, and then enters the oil tank 1 to form a circulation loop. The other path of the lubricating oil flows out from a Lub port 27 of the electro-hydraulic control valve group 6 and is respectively lubricated for a power output wet clutch 8, a four-wheel drive wet clutch 9 and a differential lock wet clutch 10 through a hydraulic radiator 13; and the lubricating oil enters the oil tank 1 after lubricating the transmission system from the transmission system lubricating damping plug 12 to form a circulation loop. And the other path controls the lubricating pressure through a lubricating pressure control valve 23 and directly enters the oil tank 1 to form a circulating loop.

When the power output control switch is turned on, the power output control valve 19 is in the energized state, and the oil passage is in the on state. Oil enters from a P port 25 of the electro-hydraulic control valve group 6 through an oil tank 1, an oil suction filter 2, a gear pump 3, a pressure oil filter 4 and a system pressure control valve 18, and the system pressure is controlled within a low-pressure range of 2 +/-0.2 MPa. At this time, the power output control valve 19 is in the on state, the emptying reversing valve 22 loses power, and the oil passage is closed. The oil liquid preferentially passes through the right position of the power output control valve 19 to charge the power output energy accumulator 7 and the power output wet clutch 8, and the power output wet clutch 8 can be stably combined due to the shunting buffer effect of the power output energy accumulator 7. And other oil is divided through the system pressure control valve 18, one way of the oil passes through the gear pump lubrication throttling valve 24, comes out of the LG port 28 of the electro-hydraulic control valve group 6, lubricates the gear pump 3 and then enters the oil tank 1 to form a circulation loop. The other path of the lubricating oil flows out from a Lub port 27 of the electro-hydraulic control valve group 6 and is respectively lubricated for a power output wet clutch 8, a four-wheel drive wet clutch 9 and a differential lock wet clutch 10 through a hydraulic radiator 13; and the lubricating oil enters the oil tank 1 after lubricating the transmission system from the transmission system lubricating damping plug 12 to form a circulation loop. And the other path controls the lubricating pressure through a lubricating pressure control valve 23 and directly enters the oil tank 1 to form a circulating loop.

When the power output control switch is closed again, the power output control valve 19 is in the power-off state and the oil passage is in the closed state. Oil enters from a P port 25 of the electro-hydraulic control valve group 6 through the oil tank 1, the oil suction filter 2, the gear pump 3 and the pressure oil filter 4, the evacuation reversing valve 22 is electrified again, the oil is shunted through the evacuation reversing valve 22 at the right position, passes through the gear pump lubrication throttle valve 24 all the way, comes out from an LG port 28 of the electro-hydraulic control valve group 6, lubricates the gear pump 3, and then enters the oil tank 1 to form a circulation loop. The other path of the lubricating oil flows out from a Lub port 27 of the electro-hydraulic control valve group 6 and is respectively lubricated for a power output wet clutch 8, a four-wheel drive wet clutch 9 and a differential lock wet clutch 10 through a hydraulic radiator 13; and the lubricating oil enters the oil tank 1 after lubricating the transmission system from the transmission system lubricating damping plug 12 to form a circulation loop. And the other path controls the lubricating pressure through a lubricating pressure control valve 23 and directly enters the oil tank 1 to form a circulating loop. The oil in the power output wet clutch 8 is bypassed to each lubricating system by the power output control valve 19 at the left position, bypassing the system pressure control valve 18, and finally returns to the oil tank 1. At this time, the pressure oil of the power output accumulator 7 is released through the left position of the power output control valve 19, so that the shunting buffering effect is achieved, and the power output wet clutch 8 can be separated stably.

2. Four-wheel drive control oil circuit route: when the four-wheel drive control switch is closed, the four-wheel drive control valve 20 is in a power-off state, and the oil passage is in a closed state. Oil enters from a P port 25 of the electro-hydraulic control valve group 6 through the oil tank 1, the oil suction filter 2, the gear pump 3 and the pressure oil filter 4, the evacuation reversing valve 22 is continuously powered after evacuation, the oil is shunted to the right through the evacuation reversing valve 22, passes through the gear pump lubricating throttle valve 24 all the way, comes out from an LG port 28 of the electro-hydraulic control valve group 6, lubricates the gear pump 3, and then enters the oil tank 1 to form a circulation loop. The other path of the lubricating oil flows out from a Lub port 27 of the electro-hydraulic control valve group 6 and is respectively lubricated for a power output wet clutch 8, a four-wheel drive wet clutch 9 and a differential lock wet clutch 10 through a hydraulic radiator 13; and the lubricating oil enters the oil tank 1 after lubricating the transmission system from the transmission system lubricating damping plug 12 to form a circulation loop. And the other path controls the lubricating pressure through a lubricating pressure control valve 23 and directly enters the oil tank 1 to form a circulating loop.

When the four-wheel drive control switch is turned on, the four-wheel drive control valve 20 is in the energized state, and the oil passage is in the on state. Oil enters from a P port 25 of the electro-hydraulic control valve group 6 through an oil tank 1, an oil suction filter 2, a gear pump 3, a pressure oil filter 4 and a system pressure control valve 18, and the system pressure is controlled within a low-pressure range of 2 +/-0.2 MPa. At this time, the four-wheel drive control valve 20 is in the on state, the emptying reversing valve 22 loses power, and the oil passage is closed. Oil liquid preferentially passes through the right position of the four-wheel drive control valve 20 to fill the four-wheel drive wet clutch 9, the rest oil liquid is divided through the system pressure control valve 18, one way of oil liquid passes through the gear pump lubrication throttling valve 24, flows out of the LG port 28 of the electro-hydraulic control valve group 6 to lubricate the gear pump 3, and then enters the oil tank 1 to form a circulation loop. The other path of the lubricating oil flows out from a Lub port 27 of the electro-hydraulic control valve group 6 and is respectively lubricated for a power output wet clutch 8, a four-wheel drive wet clutch 9 and a differential lock wet clutch 10 through a hydraulic radiator 13; and the lubricating oil enters the oil tank 1 after lubricating the transmission system from the transmission system lubricating damping plug 12 to form a circulation loop. And the other path controls the lubricating pressure through a lubricating pressure control valve 23 and directly enters the oil tank 1 to form a circulating loop.

When the four-wheel drive control switch is closed again, the four-wheel drive control valve 20 is in the power-off state, and the oil passage is in the closed state. Oil enters from a P port 25 of the electro-hydraulic control valve group 6 through the oil tank 1, the oil suction filter 2, the gear pump 3 and the pressure oil filter 4, the evacuation reversing valve 22 is electrified again, the oil is shunted through the evacuation reversing valve 22 at the right position, passes through the gear pump lubrication throttle valve 24 all the way, comes out from an LG port 28 of the electro-hydraulic control valve group 6, lubricates the gear pump 3, and then enters the oil tank 1 to form a circulation loop. The other path of the lubricating oil flows out from a Lub port 27 of the electro-hydraulic control valve group 6 and is respectively lubricated for a power output wet clutch 8, a four-wheel drive wet clutch 9 and a differential lock wet clutch 10 through a hydraulic radiator 13; and the lubricating oil enters the oil tank 1 after lubricating the transmission system from the transmission system lubricating damping plug 12 to form a circulation loop. And the other path controls the lubricating pressure through a lubricating pressure control valve 23 and directly enters the oil tank 1 to form a circulating loop. The oil in the four-wheel drive wet clutch 9 is bypassed to each lubricating system by the system pressure control valve 18 through the left position of the four-wheel drive control valve 20, and finally returns to the oil tank 1.

3. Differential lock control oil circuit route: when the differential lock control switch is closed, the differential lock control valve 21 is in a power-off state, and the oil passage is in a closed state. Oil enters from a P port 25 of the electro-hydraulic control valve group 6 through the oil tank 1, the oil suction filter 2, the gear pump 3 and the pressure oil filter 4, the evacuation reversing valve 22 is continuously powered after evacuation, the oil is shunted to the right through the evacuation reversing valve 22, passes through the gear pump lubricating throttle valve 24 all the way, comes out from an LG port 28 of the electro-hydraulic control valve group 6, lubricates the gear pump 3, and then enters the oil tank 1 to form a circulation loop. The other path of the lubricating oil flows out from a Lub port 27 of the electro-hydraulic control valve group 6 and is respectively lubricated for a power output wet clutch 8, a four-wheel drive wet clutch 9 and a differential lock wet clutch 10 through a hydraulic radiator 13; and the lubricating oil enters the oil tank 1 after lubricating the transmission system from the transmission system lubricating damping plug 12 to form a circulation loop. And the other path controls the lubricating pressure through a lubricating pressure control valve 23 and directly enters the oil tank 1 to form a circulating loop.

When the differential lock control switch is turned on, the differential lock control valve 21 is in the energized state, and the oil passage is in the on state. Oil enters from a P port 25 of the electro-hydraulic control valve group 6 through an oil tank 1, an oil suction filter 2, a gear pump 3, a pressure oil filter 4 and a system pressure control valve 18, and the system pressure is controlled within a low-pressure range of 2 +/-0.2 MPa. At this time, the differential lock control valve 21 is in a connection state, the emptying reversing valve 22 loses power, and the oil passage is closed. Oil liquid preferentially passes through the right position of the differential lock control valve 21 to charge the differential lock wet clutch 10, the rest oil liquid is divided through the system pressure control valve 18, one way of oil liquid passes through the gear pump lubrication throttling valve 24, flows out of the LG port 28 of the electro-hydraulic control valve group 6 to lubricate the gear pump 3, and then enters the oil tank 1 to form a circulation loop. The other path of the lubricating oil flows out from a Lub port 27 of the electro-hydraulic control valve group 6 and is respectively lubricated for a power output wet clutch 8, a four-wheel drive wet clutch 9 and a differential lock wet clutch 10 through a hydraulic radiator 13; and the lubricating oil enters the oil tank 1 after lubricating the transmission system from the transmission system lubricating damping plug 12 to form a circulation loop. And the other path controls the lubricating pressure through a lubricating pressure control valve 23 and directly enters the oil tank 1 to form a circulating loop.

When the differential lock control switch is closed again, the differential lock control valve 21 is in the power-off state, and the oil passage is in the closed state. Oil enters from a P port 25 of the electro-hydraulic control valve group 6 through the oil tank 1, the oil suction filter 2, the gear pump 3 and the pressure oil filter 4, the evacuation reversing valve 22 is electrified again, the oil is shunted through the evacuation reversing valve 22 at the right position, passes through the gear pump lubrication throttle valve 24 all the way, comes out from an LG port 28 of the electro-hydraulic control valve group 6, lubricates the gear pump 3, and then enters the oil tank 1 to form a circulation loop. The other path of the lubricating oil flows out from a Lub port 27 of the electro-hydraulic control valve group 6 and is respectively lubricated for a power output wet clutch 8, a four-wheel drive wet clutch 9 and a differential lock wet clutch 10 through a hydraulic radiator 13; and the lubricating oil enters the oil tank 1 after lubricating the transmission system from the transmission system lubricating damping plug 12 to form a circulation loop. And the other path controls the lubricating pressure through a lubricating pressure control valve 23 and directly enters the oil tank 1 to form a circulating loop. The oil in the differential lock wet clutch 10 bypasses the system pressure control valve 18 through the left position of the differential lock control valve 21, is distributed to each lubricating system, and finally returns to the oil tank 1.

(III) hydraulic power-assisted working oil way route:

1. when the tractor starts, as shown in fig. 1 and 2, each element is in an initial state after starting and emptying. The hydraulic power assisting device is in an independent working state, and the wet clutch is in a default non-working state.

The oil liquid passes through the oil tank 1, the oil suction filter 2, the gear pump 3 and the pressure oil line oil filter 4, and simultaneously fills the boosting energy accumulator 5 to store hydraulic pressure. Meanwhile, the oil enters from a P port of the electro-hydraulic control valve group 6, the power output control valve 19, the four-wheel drive control valve 20 and the differential lock control valve 21 are in a closed state, the evacuation reversing valve 22 is continuously powered after evacuation, the oil is shunted through the right position of the evacuation reversing valve 22, one way of the oil passes through the gear pump lubrication throttle valve 24, the oil comes out from an LG port 28 of the electro-hydraulic control valve group 6 and enters the oil tank 1 after lubricating the gear pump 3, and a circulation loop is formed. The other path of the lubricating oil flows out from a Lub port 27 of the electro-hydraulic control valve group 6 and is respectively lubricated for a power output wet clutch 8, a four-wheel drive wet clutch 9 and a differential lock wet clutch 10 through a hydraulic radiator 13; and the lubricating oil enters the oil tank 1 after lubricating the transmission system from the transmission system lubricating damping plug 12 to form a circulation loop. And the other path controls the lubricating pressure through a lubricating pressure control valve 23 and directly enters the oil tank 1 to form a circulating loop.

When the clutch pedal is not depressed, the clutch booster master cylinder 14 is in the off state. When the clutch pedal is depressed, the clutch booster master cylinder 14 is in the on-state. The evacuation diverter valve 22 loses power and closes the oil gallery. Oil enters from a P port 25 of the electro-hydraulic control valve group 6 through the oil tank 1, the oil suction oil filter 2, the gear pump 3 and the pressure oil line oil filter 4, passes through the system pressure control valve 18, controls the system pressure within a low-pressure range of 2 +/-0.2 MPa, and is distributed to each lubricating system or oil return tank. Meanwhile, the clutch booster sub-cylinder 15 is filled with liquid through the clutch booster master cylinder 14, and the power assisting effect is achieved. And simultaneously, the boosting energy accumulator 5 is filled with liquid and stores the liquid pressure. When the oil in the sub-cylinder 15 of the clutch booster is full and the clutch pedal is not loosened after being stepped. The clutch booster master cylinder 14 is in a connection oil drainage state, and oil is released to drain through the clutch booster master cylinder 14 and returns to an oil tank. Clutch booster master cylinder 14

2. When the tractor is not started, as shown in fig. 1 and 2, the elements are in an initial state after starting and emptying, and the boosting accumulator 5 stores hydraulic pressure.

When the clutch pedal is not stepped on. The clutch booster master cylinder 14 is in the off state. When the clutch pedal is depressed, the clutch booster master cylinder 14 is in the on-state. The pressure oil of the booster accumulator 5 is released through the middle position of the clutch booster master pump 14 to play a role of a temporary power source, and the clutch booster sub-cylinder 15 is filled with liquid to play a boosting role. When the oil in the sub-cylinder 15 of the clutch booster is full and the clutch pedal is not loosened after being stepped. The clutch booster master cylinder 14 is in a connection oil drainage state, and pressure oil of the boosting energy accumulator 5 is released and drained through the right position of the clutch booster master cylinder 14.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or recited in detail in a certain embodiment.

It should be noted that the above embodiments can be freely combined as necessary. The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A tractor low pressure electricity liquid control system which characterized in that includes:

the gear pump is connected with the oil tank and used for pumping the oil;

2. The tractor low pressure electro-hydraulic control system of claim 1, further comprising: a system pressure control valve;

3. The tractor low-pressure electro-hydraulic control system of claim 2, wherein:

the plurality of electromagnetic valves comprise power output control valves, four-wheel drive control valves and differential lock control valves, and the electro-hydraulic control valve group is provided with a port P, a port PT0, a port 4WD and a port DL;

4. The tractor low-pressure electro-hydraulic control system of claim 3, wherein:

the oil path comprises a first oil return path;

5. The tractor low-pressure electro-hydraulic control system of claim 4, wherein:

the oil circuit further comprises a second transmission system lubricating oil circuit;

6. The tractor low-pressure electro-hydraulic control system of claim 5, wherein:

the oil circuit also comprises a third gear pump lubricating oil circuit;

7. The tractor low-pressure electro-hydraulic control system of claim 6, wherein:

and a wet clutch lubricating oil way is arranged on the third gear pump lubricating oil way and/or the second transmission system lubricating oil way, and the liquid outlet end of the wet clutch lubricating oil way is respectively communicated to the power output wet clutch, the four-wheel drive wet clutch and the differential lock wet clutch.

8. The tractor low pressure electro-hydraulic control system of claim 3, further comprising: a power take-off accumulator;

9. The tractor low pressure electro-hydraulic control system of claim 8, further comprising:

the clutch boosting system is arranged between the oil output end of the gear pump and the port P and comprises a clutch booster master cylinder and a clutch booster oil distribution cylinder, one end of the clutch booster master cylinder is connected with the liquid outlet end of the pressure oil line oil filter, and the other end of the clutch booster master cylinder is connected with the clutch booster oil distribution cylinder;

10. The tractor low pressure electro-hydraulic control system of claim 9, further comprising: a boost accumulator;