Hydraulic system for a tractor and tractor

Abstract

The application discloses a tractor hydraulic system and a tractor, and relates to the field of tractors, and aims to realize the composite work of a suspension lifting system and an output system, and the comprehensive adjustment control of a plowing depth force position. The tractor hydraulic system comprises a main pump, a hydraulic oil pumping oil path connected to an oil outlet of the main pump, a suspension lifting system, an auxiliary output system, and an output multi-way valve. The suspension lifting system comprises a lifting oil cylinder used for driving the hydraulic suspension of the tractor and a lifting control valve used for controlling the lifting oil cylinder. The auxiliary output system comprises the output multi-way valve. A multi-way valve oil inlet of the output multi-way valve and a lifting valve oil inlet of the lifting control valve are connected to the hydraulic oil pumping oil path in parallel. A first auxiliary oil inlet oil path is connected between the hydraulic oil pumping oil path and the multi-way valve oil inlet. An auxiliary control switch valve used for controlling the on-off of the oil path is arranged in the first auxiliary oil inlet oil path. The tractor hydraulic system can realize the composite work of the suspension lifting system and the output system, can realize the comprehensive adjustment control of the plowing depth force position, has no redundant capacity loss when the system is not working and when the auxiliary output is independently working, and is more energy-saving.

Description

Technical Field

[0001] This application belongs to the field of tractor control, and specifically relates to a tractor and its hydraulic system. Background Technology

[0002] As a self-propelled power unit, tractors can tow and drive agricultural implements to complete various tasks, such as plowing. Existing tractors are equipped with a small hydraulic power system, in which the hydraulic pump is driven by a diesel engine and is always in operation. It pumps hydraulic oil to the hydraulic suspension and working machinery to achieve hydraulic lifting and adjustment of the attitude of the agricultural implements.

[0003] However, these tractor-mounted hydraulic systems cannot achieve combined lifting and auxiliary output operations, resulting in poor system adaptability. Furthermore, the system's electronic lifting control cannot simultaneously meet both high-pressure control and force-position integrated adjustment control, failing to satisfy the demands of most high-pressure operating conditions in China. In addition, the auxiliary output lacks adjustable flow rate, making flow control uncontrollable when using multiple composite implements, thus affecting work performance and efficiency. Summary of the Invention

[0004] The purpose of this application is to provide a tractor hydraulic system and a tractor to improve the working performance and control performance of the tractor hydraulic system.

[0005] To achieve the above objectives, this application provides a tractor hydraulic system, comprising:

[0006] The main pump, whose outlet is connected to a hydraulic oil pump supply circuit;

[0007] A suspension lifting system includes a lifting cylinder for driving a hydraulic suspension of a tractor and a lifting control valve for controlling the lifting cylinder;

[0008] An auxiliary output system includes an output multi-way valve, wherein the multi-way valve inlet of the output multi-way valve and the lift valve inlet of the lift control valve are connected in parallel to the hydraulic oil pump delivery circuit;

[0009] The hydraulic oil pump delivery circuit is connected to the multi-way valve inlet via a first auxiliary oil inlet circuit, which is equipped with an auxiliary control switch valve for controlling the on / off state of the oil circuit.

[0010] In some embodiments, the tractor hydraulic system further includes a second auxiliary oil inlet circuit connected between the hydraulic oil pump delivery circuit and the multi-way valve inlet. The second auxiliary oil inlet circuit is provided with a priority valve for controlling the on / off state of the oil circuit. The priority valve is a hydraulically controlled pilot valve and includes a first hydraulically controlled end connected to the lift valve inlet and a second hydraulically controlled end connected to the rodless chamber working oil circuit of the lift cylinder and provided with a compression spring.

[0011] In some embodiments, the second auxiliary oil inlet circuit is further provided with a check valve connected in series with the priority valve. The check valve is configured to allow hydraulic oil to flow from the hydraulic oil pump delivery circuit to the inlet of the multi-way valve and to cut off the flow in the reverse direction.

[0012] In some embodiments, the lift control valve includes:

[0013] The main directional valve is connected at its front end to the oil inlet of the lifting valve, and at its rear end to the working oil inlet, which is connected to the working oil circuit of the rod chamber and the working oil circuit of the rodless chamber of the lifting cylinder, respectively.

[0014] A lift valve is installed in the working oil circuit of the rodless chamber and is used to control the on / off state of the working oil circuit of the rodless chamber.

[0015] A descending valve is installed in the rodless chamber return oil circuit and is used to control the opening and closing of the rodless chamber return oil circuit, which is a branch oil circuit that returns the working oil circuit of the rodless chamber to the hydraulic oil tank.

[0016] In some embodiments, the lifting cylinder is a single cylinder; or, the lifting cylinder is a double cylinder, wherein the rod-side chambers of the double cylinders are interconnected and the rodless chambers of the double cylinders are interconnected.

[0017] In some embodiments, the lift control valve includes:

[0018] A compensation valve is connected in series with the lift valve in the working oil circuit of the rodless chamber and is located between the lift valve and the main directional valve;

[0019] The compensation valve is a hydraulically controlled directional valve with an involute opening valve port, and the hydraulically controlled chambers at both ends are respectively connected to the front end and the rear end of the lift valve.

[0020] In some embodiments, the lifting valve and the lowering valve are electro-proportional control valves.

[0021] In some embodiments, the tractor hydraulic system includes:

[0022] A tension sensor is used to detect the tension of the hydraulic suspension;

[0023] A position sensor is used to detect the real-time working position of the working attachment connected to the output multi-way valve;

[0024] The controller is used to control the valve position switching action and valve core opening of the lifting valve and the lowering valve respectively, based on the detection signals of the tension sensor and the position sensor, under the comprehensive adjustment condition of tillage depth and force.

[0025] In some embodiments, the output multi-way valve includes a multi-valve disc, and each valve disc has a proportional pilot solenoid valve at both ends of its directional valve for controlling the valve core opening.

[0026] In some embodiments, the output multi-way valve is provided with a solenoid valve pilot oil circuit that connects from the oil inlet of the multi-way valve to each of the proportional pilot solenoid valves, and the solenoid valve pilot oil circuit is provided with a pressure reducing valve adjacent to the oil inlet of the multi-way valve.

[0027] This application also provides a tractor that includes the tractor hydraulic system described above.

[0028] In the tractor and its hydraulic system of this application, the suspension lifting system and the auxiliary output system are connected in parallel. The pumping pressure oil of the main pump can flow to the lifting control valve or to the output multi-way valve, thus enabling the two systems to work in combination to meet more working conditions, including comprehensive adjustment and control of tillage depth and force. Moreover, there is no excess energy loss when the hydraulic system is not working or when the auxiliary output works independently, making the system energy-saving. Therefore, the working performance of the tractor hydraulic system is improved, and the control performance of the tractor is further enhanced.

[0029] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0030] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without any inventive effort. In the drawings:

[0031] Figure 1 Hydraulic schematic diagram of an existing tractor hydraulic system;

[0032] Figure 2 A hydraulic schematic diagram of a tractor hydraulic system according to a specific embodiment of this application;

[0033] Hydraulic schematic diagram of a tractor hydraulic system;

[0034] Figure 3 A control principle diagram of a tractor hydraulic system under integrated tillage depth and force adjustment conditions according to a specific embodiment of this application; and

[0035] Figure 4 for Figure 2The diagram shows the combination of solenoid valve reversing actions under various control conditions in the tractor hydraulic system. White circles represent electromagnets that are not energized, black circles represent electromagnets that are energized, and cross-sectional circles represent actions taken in real time based on sensor signals.

[0036] Explanation of reference numerals in the attached figures

[0037] 1. Hydraulic oil tank 2. Return oil filter

[0038] 3. Auxiliary control switching valve; 4. Output multi-way valve

[0039] 5 Quick-change coupling 6 Lifting cylinder

[0040] 7. Lift control valve 8. Filter

[0041] 9 Main pump 10 Check valve

[0042] 11 Oil Inlet Connection 12 Auxiliary Output Connection

[0043] 13 Electrical control output connection 14 Tail connection

[0044] 15. Front compensation valve

[0045] 41 Pressure reducing valve 42 Proportional pilot-operated solenoid valve

[0046] 70 Priority valve; 71 Main directional valve

[0047] 72 Compensation valve 73 Lift valve

[0048] 74. Downward valve

[0049] P1 is the inlet port of the lift valve, and P2 is the inlet port of the multi-way valve.

[0050] L0 Hydraulic oil pump supply circuit; L1 First auxiliary oil inlet circuit.

[0051] L2 Second Auxiliary Oil Inlet Circuit; L3 Rodless Chamber Working Oil Circuit

[0052] L4 Rod chamber working oil circuit; L5 Rodless chamber return oil circuit

[0053] L6 Solenoid Valve Pilot Oil Circuit Detailed Implementation

[0054] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0055] The following description, with reference to the accompanying drawings, describes a tractor hydraulic system and a tractor according to this application.

[0056] Figure 1This is a schematic diagram of a conventional tractor hydraulic system. The multi-way valves in the hydraulic system include an inlet valve 11, an auxiliary output valve 12, an electronic control output valve 13, a tail valve 14, and a front compensation valve 15. The safety valve in the inlet valve 11 controls the system's maximum pressure, and the tail valve 14 connects to the lifting cylinder of the hydraulic suspension, serving as the lifting operation.

[0057] When the system is not operating, all solenoid valves are in the state shown in the diagram. Hydraulic oil passes through the front solenoid valve in the electronic control output link 13 to the front compensation valve 15 in the tail link 14. Pressure opens the spring of the front compensation valve 15, allowing oil to enter the return port T. During lifting operations, solenoid valve Y7b in the electronic control output link 13 is de-energized, while Y1b and Y3b in the tail link 14 are simultaneously energized, enabling the lifting cylinder to perform the lifting operation. During lowering operations, Y2b and Y4b in the tail link 14 are simultaneously energized, enabling the cylinder to retract. When the auxiliary output link 12 is operating, Y7b in the electronic control output link 13 is energized, cutting off the oil supply to the tail link 14 and enabling the auxiliary output link to deliver oil. At this time, no hydraulic oil enters the tail link 14, and it cannot operate simultaneously.

[0058] It is evident that this tractor's hydraulic system, regardless of whether it is operating or not, must constantly overcome the spring force of the front compensating valve 15 to allow oil to flow in and out. Therefore, the system always experiences a certain amount of pressure energy consumption, which can easily cause valve overheating, leading to a risk of high system temperature. Furthermore, the system's high energy consumption contradicts energy-saving principles. In particular, the output and lifting linkages cannot operate in conjunction. When the output linkage is operating, the lifting cylinder cannot perform lifting and lowering operations. Moreover, the auxiliary output linkage 12 cannot achieve flow regulation control, failing to meet the different flow requirements of various implements (such as seeders and fertilizer spreaders).

[0059] Specifically, this application discloses a novel hydraulic system for tractors. For example... Figure 2 As shown, in one specific embodiment, the hydraulic system includes:

[0060] Main pump 9, the main pump outlet of which is connected to hydraulic oil pump delivery circuit L0;

[0061] The suspension lifting system includes a lifting cylinder 6 for driving the tractor and a lifting control valve 7 for controlling the lifting cylinder 6.

[0062] The auxiliary output system includes an output multi-way valve 4, the multi-way valve inlet P2 of the output multi-way valve 4 and the lift valve inlet P1 of the lift control valve 7 are connected in parallel to the hydraulic oil pump delivery circuit L0.

[0063] Among them, the hydraulic oil pump delivery circuit L0 is connected to the multi-way valve inlet P2 by a first auxiliary oil inlet circuit L1, and the first auxiliary oil inlet circuit L1 is equipped with an auxiliary control switch valve 3 for controlling the opening and closing of the oil circuit.

[0064] Compared to traditional tractor hydraulic systems, where the suspension lifting system and auxiliary output system are connected in series directly or through a multi-way valve, the tractor hydraulic system of this application connects the two working systems in parallel and is specially equipped with an auxiliary control switch valve 3 to control the opening and closing of the first auxiliary oil inlet circuit L1 in a timely manner, thereby enabling the two systems to work in combination and adapt to more working conditions.

[0065] Specifically, the tractor hydraulic system of this embodiment also includes a second auxiliary oil inlet circuit L2 connected between the hydraulic oil pump delivery circuit L0 and the multi-way valve inlet P2. The second auxiliary oil inlet circuit L2 is provided with a priority valve 70 for controlling the on / off of the oil circuit. The priority valve 70 is a hydraulically controlled pilot valve and includes a first hydraulically controlled end connected to the lift valve inlet P1 and a second hydraulically controlled end connected to the rodless chamber working oil circuit L3 of the lift cylinder 6 and provided with a compression spring.

[0066] When only the auxiliary control switch valve 3 is installed, if the first auxiliary oil inlet circuit L1 is open and both working systems operate simultaneously, the hydraulic oil may be preferentially distributed to the working attachment drive mechanism connected to the quick-change connector 5, rather than being preferentially supplied to the lifting control valve 7 as intended. Therefore, a second auxiliary oil inlet circuit L2 is added in parallel with the first auxiliary oil inlet circuit L1 and equipped with a priority valve 70. The priority valve 70 ensures that the pressurized oil in the hydraulic oil pump delivery circuit L0 is preferentially supplied to the suspension lifting system. Specifically, since the priority valve 70 is a hydraulically controlled pilot valve, the first hydraulically controlled end is connected to the lifting valve inlet P1, and the second hydraulically controlled end is a spring end connected to the rodless chamber of the lifting cylinder 6. Therefore, when the suspension lifting system and the auxiliary output system are working in combination, the first auxiliary oil inlet circuit L1 can be cut off, so that the pressurized oil in the hydraulic oil pump delivery circuit L0, while being supplied to the lifting valve inlet P1 of the lifting control valve 7, can also be supplied to the multi-way valve inlet P2 of the output multi-way valve 4 through the second auxiliary oil inlet circuit L2. However, because the second hydraulic control end of the priority valve 70 is a spring end, the valve opening of the priority valve 70 is limited, and the valve core cannot be fully opened. Especially when the lifting cylinder 6 is under load, the oil pressure in the rodless chamber is further fed back to the second hydraulic control end, further limiting the valve opening of the priority valve 70. In other words, when the two working systems are working simultaneously, due to the presence of the priority valve 70, the pumping hydraulic oil of the main pump 9 is preferentially supplied to the lifting control valve 7, and then partially supplied to the output multi-way valve 4, achieving compound operation while prioritizing the flow of the lifting system.

[0067] To prevent backflow of oil in the oil circuit, a check valve 10 connected in series with the priority valve 70 can also be provided in the second auxiliary oil inlet circuit L2. The check valve 10 is configured to allow hydraulic oil to flow from the hydraulic oil pump delivery circuit L0 to the multi-way valve inlet P2 and to cut off in the reverse direction.

[0068] In this embodiment, as an example, the lifting control valve 7 may include:

[0069] The main directional valve 71 is connected to the oil inlet P1 of the lifting valve at the front end, and the working oil port at the rear end is connected to the working oil circuit L4 of the rod chamber and the working oil circuit L3 of the rodless chamber of the lifting cylinder 6 respectively.

[0070] The lift valve 73 is installed in the rodless chamber working oil circuit L3 and is used to control the on / off state of the rodless chamber working oil circuit L3; and

[0071] The descending valve 74 is installed in the rodless chamber return oil circuit L5 and is used to control the opening and closing of the rodless chamber return oil circuit L5. The rodless chamber return oil circuit L5 is a branch oil circuit that returns the rodless chamber working oil circuit L3 to the hydraulic oil tank 1.

[0072] As can be seen, the lifting control valve 7 in this embodiment includes three basic valve components for controlling the lifting cylinder 6: a main directional valve 71, a lifting valve 73, and a lowering valve 74. The main directional valve 71 is a three-position four-way valve. By switching the main directional valve 71 between the three positions, the pressure oil at the lifting valve inlet P1 can be directed to the rod chamber or rodless chamber of the lifting cylinder 6, or the oil chamber can be connected to the return oil, making the cylinder float, thus achieving high-pressure control of the double-acting cylinder. Since a rodless chamber return oil circuit L5 is provided, if the main directional valve 71 only switches between the middle and right positions shown in the figure, the pressure oil at the lifting valve inlet P1 can be directed to the rodless chamber of the lifting cylinder 6, or the oil chamber can be connected to the return oil, making the cylinder float. The cylinder can then retract through the return oil from the rodless chamber, achieving non-high-pressure control of the single-acting cylinder.

[0073] Depending on the tractor specifications, the lifting cylinder 6 can be a single cylinder; alternatively, the lifting cylinder 6 can also be a double cylinder. When using a double cylinder, the rod-side chambers of the two cylinders are interconnected, and their rodless chambers are also interconnected. Figure 2 As shown.

[0074] Furthermore, the lifting control valve 7 may also include:

[0075] The compensation valve 72 is connected in series with the lift valve 73 in the rodless chamber working oil circuit L3 and is located between the lift valve 73 and the main directional valve 71.

[0076] Among them, the compensation valve 72 is a hydraulically controlled directional valve with an involute valve orifice, and the hydraulically controlled chambers at both ends are respectively connected to the front end and the rear end of the lift valve 73.

[0077] Those skilled in the art will understand that the compensating valve 72 is provided here to achieve pressure compensation. When the pressure in the rodless chamber is high, the flow port of the compensating valve 72 is larger, and conversely, when the pressure in the rodless chamber is relatively low, the opening of the flow port becomes smaller, so that the flow output from the working oil circuit L3 to the rodless chamber remains sufficient and stable.

[0078] Furthermore, in this embodiment, the lifting valve 73 and the lowering valve 74 are electro-proportional control valves. The opening degree of their respective valve ports is controlled by the end electromagnet, thereby controlling the flow rate of the rodless chamber working oil circuit L3 and the rodless chamber return oil circuit L5, so that the flow rate can be adjusted accordingly according to the working requirements.

[0079] In particular, such as Figure 3 As shown, the tractor hydraulic system of this embodiment may further include:

[0080] A tension sensor is used to detect the tension in a hydraulic suspension.

[0081] A position sensor is used to detect the real-time working position of the working attachment connected to the output multi-way valve 4;

[0082] The controller is used to control the valve position switching action and valve core opening of the lifting valve 73 and the lowering valve 74 respectively, based on the detection signals of the tension sensor and the position sensor, under the comprehensive adjustment of tillage depth and position.

[0083] exist Figure 2 Based on the hydraulic system of the tractor shown, by adding a tension sensor and a position sensor, as well as a controller that communicates with the two sensors, it is possible to control the lifting valve 73 and / or the lowering valve 74 under the comprehensive adjustment of tillage depth and force, thereby controlling the extension and retraction of the lifting cylinder 6, so that the hydraulic suspension is raised, and thus the agricultural implement is raised, reducing the working load pressure of the agricultural implement.

[0084] exist Figure 2 In this configuration, the output multi-way valve 4 includes multiple valve sections. Each valve section has a proportional pilot solenoid valve 42 at both ends of its directional valve for controlling the valve core opening. The proportional pilot solenoid valve 42 controls the pilot oil flowing to the hydraulic control chamber at the end of the directional valve, thereby controlling the directional valve's switching direction and valve core opening, and ultimately regulating the flow rate supplied to the actuator of the agricultural machinery. Further details can be found in the documentation. Figure 2 The output multi-way valve 4 also includes a solenoid valve pilot oil circuit L6 that connects from the multi-way valve inlet P2 to each proportional pilot solenoid valve 42. The pilot oil in the solenoid valve pilot oil circuit L6 flows to the end hydraulic control chamber of the directional valve to control the directional valve's switching action. The solenoid valve pilot oil circuit L6 is equipped with a pressure reducing valve 41 adjacent to the multi-way valve inlet P2 to control the pressure of the pilot oil.

[0085] The aforementioned tractor hydraulic system can be applied to common tractors. It not only enables combined hydraulic suspension lifting control and auxiliary output control, but also achieves integrated force-position adjustment control, meaning it combines tractor plowing position and traction force to control tillage depth. Furthermore, it can adjust the flow rate supplied to the implement actuators according to the implements' working needs, thus achieving adjustable auxiliary output flow.

[0086] Specifically, see Figure 2 , Figure 4 The hydraulic oil pumped by the main pump 9 from the hydraulic oil tank 1 is filtered by the filter 8 in the hydraulic oil pump delivery circuit L0, and then flows to the lift valve inlet P1 of the lift control valve 7 and the multi-way valve inlet P2 of the output multi-way valve 4. The output multi-way valve 4 is a pilot control valve that controls the operation of agricultural implements, while the lift control valve 7 controls the movement of the lift cylinder 6 of the hydraulic suspension. The auxiliary control switch valve 3 controls the system's maximum working pressure and controls both individual output operation and combined lift and output operation.

[0087] Combination Figure 2 , Figure 4 When the system is not working, it is in a neutral unloaded state, and the system oil circuit is as follows: Figure 2 As shown, electromagnets DT1 to DT4 are not energized, while DT5 is energized, meaning the main directional valve 71 is in the intermediate cut-off position, and the first auxiliary oil inlet circuit L1 is open. The hydraulic oil drawn by the main pump 9 passes through the first auxiliary oil inlet circuit L1, the auxiliary control switch valve 3, and the intermediate positions of each directional valve in the output multi-way valve 4, and then directly returns to the hydraulic oil tank 1 through the return oil circuit equipped with the return oil filter 2.

[0088] When only the auxiliary output system is working, the auxiliary control switch valve 3 is energized, and the first auxiliary oil inlet circuit L1 is opened; according to the quick-change connector 5 connected to the working agricultural implement, the corresponding proportional pilot solenoid valve 42 in the corresponding control output multi-way valve 4 is energized, so that the output circuit works, and the proportional pilot solenoid valve 42 can adjust the opening degree to realize the auxiliary output flow regulation.

[0089] When the suspension lifting system is working and the lifting cylinder 6 rises, the solenoid DT5 of the auxiliary control switch valve 3 is not energized, and the first auxiliary oil inlet circuit L1 is cut off; the solenoid DT1 of the main directional valve 71 and the solenoid DT3 of the lifting valve 73 in the lifting control valve 7 are energized at the same time, and the pressure oil of the hydraulic oil pump delivery circuit L0 flows into the rodless chamber of the lifting cylinder 6 through the oil inlet P1 of the lifting valve, the right position of the main directional valve 71, and the rodless chamber working oil circuit L3, driving the piston rod of the lifting cylinder 6 to extend. At the same time, the oil in the rod chamber flows back to the hydraulic oil tank 1 through the rod chamber working oil circuit L4, the right position of the main directional valve 71, and the return oil port of the main directional valve 71.

[0090] When the lifting cylinder descends, electromagnet DT5 is de-energized, and the first auxiliary oil inlet circuit L1 is cut off. Simultaneously, electromagnet DT2 of the main directional valve 71 and electromagnet DT4 of the lowering valve 74 within the lifting control valve 7 are energized, switching the main directional valve 71 to the left position, and the rodless chamber return oil circuit L5 is opened. Pressure oil from the hydraulic pump supply circuit L0 flows into the rod chamber of the lifting cylinder 6 via the lifting valve inlet P1, the left position of the main directional valve 71, and the rod chamber working oil circuit L4, driving the piston rod of the lifting cylinder 6 to retract. Simultaneously, oil from the rodless chamber flows back to the hydraulic oil tank 1 via the rodless chamber working oil circuit L3 and the rodless chamber return oil circuit L5.

[0091] When the lifting cylinder 6 is in a floating state, only the electromagnet DT4 of the lowering valve 74 is energized, and the oil return circuit L5 of the rodless chamber is open. The oil in the rod chamber of the lifting cylinder 6 returns via the neutral position of the main directional valve 71, and the oil in the rodless chamber of the lifting cylinder 6 returns via the rodless chamber working circuit L3 and the rodless chamber return circuit L5. Therefore, both the rodless and rod chambers of the lifting cylinder 6 are connected for oil return, allowing the agricultural implement to float by its own weight.

[0092] When the suspension lifting system and auxiliary output system operate in combination, the electromagnet DT5 is not energized, and the first auxiliary oil inlet circuit L1 is shut off. Part of the pressurized oil from the hydraulic pump's delivery circuit L0 flows to the lifting valve inlet P1 of the lifting control valve 7, while the other part flows through the priority valve 70, check valve 10, and the second auxiliary oil inlet circuit L2 to the multi-way valve inlet P2 of the output multi-way valve 4. As mentioned earlier, the priority valve 70 controls the simultaneous operation of the suspension lifting system and auxiliary output system, with priority given to the flow rate of the suspension lifting system.

[0093] During the integrated adjustment of tillage depth and position, the suspension lifting system and auxiliary output system work in tandem. Electromagnet DT5 is de-energized, while electromagnet DT1 in the main directional valve 71 within the lifting control valve 7 is energized, and DT2 is de-energized. DT3 in the lifting valve 73 and DT4 in the lowering valve 74 control the switching action of the electromagnets and the valve opening size based on signals from the tension sensor and position sensor. Specifically, the signals from the tension sensor and position sensor, after being converted by the controller, correspond to the current signals of the electromagnets, controlling the valve reversing action and valve core opening of the lifting valve 73 and lowering valve 74 within the lifting control valve 7. For example, when the current tillage position of the agricultural implement is deep, resulting in a large tension in the hydraulic suspension, the controller detects the relevant tillage depth and tension signals, and can correspondingly control the lifting valve 73 to open and control the valve opening, driving the lifting cylinder 6 to rise and controlling the lifting speed.

[0094] In summary, the tractor hydraulic system of this application offers more comprehensive functions, suitable for a wider range of working conditions. It can achieve combined lifting and auxiliary output operations, integrated adjustment and control of tillage depth and force, and adjustable flow rate for the output working sequence. Specifically, the system's auxiliary output and suspension lifting can operate simultaneously, meeting the combined working requirements of implement suspension and output, while prioritizing suspension lifting during combined operations. The adjustable flow rate of the system's auxiliary output working sequence better meets the constant or stable flow rate requirements of different implements. The load sensitivity and integrated force and position adjustment control of the lifting control valve are more sensitive and accurate. Figure 1 The directional valve in the lift valve will have a certain impact on the lifting load sensitivity and compensation pressure and flow feedback signal.

[0095] Furthermore, the design of the lifting control valve 7 allows for both double-acting, high-pressure control of the lifting cylinder 6 and single-acting, non-high-pressure control. When the system is not in operation, all valves are in their initial state, with no additional energy loss, making it more environmentally friendly and energy-efficient; in comparison, Figure 1 The front compensation valve 15 always consumes (5~10) bar of energy, and the valve is prone to overheating and high temperature, resulting in significant energy loss.

[0096] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0097] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0098] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0099] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A tractor hydraulic system, characterized in that, The tractor hydraulic system includes: The main pump (9) has a hydraulic oil pump delivery circuit (L0) connected to its main pump outlet. The suspension lifting system includes a lifting cylinder (6) for driving the hydraulic suspension of the tractor and a lifting control valve (7) for controlling the lifting cylinder (6). The auxiliary output system includes an output multi-way valve (4), the multi-way valve inlet (P2) of the output multi-way valve (4) and the lift valve inlet (P1) of the lift control valve (7) are connected in parallel to the hydraulic oil pump delivery circuit (L0). The second auxiliary oil inlet circuit (L2) is connected between the hydraulic oil pump delivery circuit (L0) and the multi-way valve inlet (P2). The second auxiliary oil inlet circuit (L2) is provided with a priority valve (70) for controlling the opening and closing of the oil circuit. The priority valve (70) is a hydraulic pilot valve and includes a first hydraulic control end connected to the lift valve inlet (P1) and a second hydraulic control end connected to the rodless chamber working oil circuit (L3) of the lift cylinder (6) and provided with a compression spring. The opening degree of the priority valve (70) is limited. The hydraulic oil pump delivery circuit (L0) is connected to the multi-way valve inlet (P2) by a first auxiliary oil inlet circuit (L1), and the first auxiliary oil inlet circuit (L1) is provided with an auxiliary control switch valve (3) for controlling the opening and closing of the oil circuit.

2. The tractor hydraulic system according to claim 1, characterized in that, The second auxiliary oil inlet circuit (L2) is also provided with a one-way valve (10) connected in series with the priority valve (70). The one-way valve (10) is configured to allow hydraulic oil to flow from the hydraulic oil pump delivery circuit (L0) to the multi-way valve inlet (P2) and to cut off in the reverse direction.

3. The tractor hydraulic system according to any one of claims 1 to 2, characterized in that, The lift control valve (7) includes: The main directional valve (71) is connected at the front end to the oil inlet (P1) of the lifting valve, and at the rear end to the working oil inlet, which is connected to the rod chamber working oil circuit (L4) and the rodless chamber working oil circuit (L3) of the lifting cylinder (6). A lift valve (73) is provided in the rodless chamber working oil circuit (L3) and is used to control the opening and closing of the rodless chamber working oil circuit (L3); A descending valve (74) is installed in the rodless chamber return oil passage (L5) and is used to control the opening and closing of the rodless chamber return oil passage (L5). The rodless chamber return oil passage (L5) is a branch oil passage from the rodless chamber working oil passage (L3) back to the hydraulic oil tank (1).

4. The tractor hydraulic system according to claim 3, characterized in that, The lifting cylinder (6) is a single cylinder; or, the lifting cylinder (6) is a double cylinder, wherein the rod chambers of the double cylinders are interconnected and the rodless chambers of the double cylinders are interconnected.

5. The tractor hydraulic system according to claim 3, characterized in that, The lift control valve (7) includes: The compensation valve (72) is connected in series with the lift valve (73) in the rodless chamber working oil circuit (L3) and located between the lift valve (73) and the main directional valve (71); The compensation valve (72) is a hydraulically controlled directional valve with an involute valve opening, and the hydraulically controlled chambers at both ends are respectively connected to the front end and the rear end of the lift valve (73).

6. The tractor hydraulic system according to claim 3, characterized in that, The lifting valve (73) and the lowering valve (74) are electro-proportional control valves.

7. The tractor hydraulic system according to claim 6, characterized in that, The tractor hydraulic system includes: A tension sensor is used to detect the tension of the hydraulic suspension; A position sensor is used to detect the real-time working position of the working attachment connected to the output multi-way valve (4); The controller is used to control the valve position switching action and valve core opening of the lifting valve (73) and the lowering valve (74) respectively according to the detection signals of the tension sensor and the position sensor under the comprehensive adjustment of tillage depth and force.

8. The tractor hydraulic system according to any one of claims 1 to 2, characterized in that, The output multi-way valve (4) includes a multi-valve plate, and each valve plate has a proportional pilot solenoid valve (42) at both ends of the reversing valve for controlling the valve core opening.

9. The tractor hydraulic system according to claim 8, characterized in that, The output multi-way valve (4) is provided with a solenoid valve pilot oil passage (L6) that connects from the multi-way valve inlet (P2) to each of the proportional pilot solenoid valves (42). The solenoid valve pilot oil passage (L6) is provided with a pressure reducing valve (41) adjacent to the multi-way valve inlet (P2).

10. A tractor, characterized in that, The tractor includes a tractor hydraulic system according to any one of claims 1 to 9.

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