A tractor pilot hydraulic control hydraulic system

Abstract

The utility model relates to tractor control technical field, concretely relates to a tractor pilot hydraulic control hydraulic system, in the utility model, electric control poppet valve and hydraulic output valve group are all electro-hydraulic pilot control, are pushed by hydraulic oil and move main valve to prevent the valve core to be stuck, or stuck valve caused by the thrust limit of electromagnet, in the utility model, the priority valve in electric control poppet valve can realize flow shunt, under the premise of giving priority to satisfying electric control poppet, the redundant flow is provided for hydraulic output valve group use, and the EF mouth is set up on the hydraulic output valve group, can connect tractor front loading valve group or other execution equipment, thereby realize single gear pump control poppet valve, hydraulic output valve and tractor front loading and so on multiple hydraulic actuators's action, in the utility model, hydraulic output valve group and electric control poppet valve all have manual operation mode, also can be operated through manual mode under the condition of electrical system failure, to ensure the emergency need.

Description

Technical Field

[0001] This utility model relates to the field of tractor control technology, specifically to a tractor pilot hydraulic control system. Background Technology

[0002] With the development of large-scale and mechanized agriculture this year, agricultural machinery is also rapidly being updated and developed. In particular, tractors, as power output devices, need to work with a variety of agricultural equipment. The drive and control of tractors require extensive use of hydraulic control. Among them, the electric lift valve controls the flow of hydraulic oil through electrical signals, thereby controlling the action of the lifter. The hydraulic output valve group distributes hydraulic oil to other actuators. In the existing technology, when dealing with the working requirements of high pressure and high flow, the stability of the system is easily affected by valve core jamming or solenoid valve thrust problems. Utility Model Content

[0003] The purpose of this utility model is to provide a reasonably designed pilot hydraulic control system for tractors that addresses the defects and shortcomings of the existing technology, thereby solving the aforementioned deficiencies.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: It includes an electrically controlled lifting valve and a hydraulic output valve assembly connected thereto. The electrically controlled lifting valve is provided with a priority valve. The upstream end of the priority valve is connected to a gear pump that draws oil from the oil tank. The rear end of the priority valve is provided with a main control valve. The downstream end of the priority valve is connected to the main control valve and the hydraulic output valve assembly respectively. A proportional valve is also connected in the oil circuit at the front end of the priority valve. The rear end of the proportional valve is connected to the main control valve through a throttle orifice. A hydraulic valve is connected behind the main control valve. The rear end of the hydraulic valve is connected to the lifting cylinder. A switching valve is connected in the oil circuit between the main control valve and the hydraulic valve. The rear end of the switching valve is connected to the hydraulic valve. The connected oil circuit is connected to the oil port of the lifting cylinder through a throttle orifice.

[0005] Preferably, the hydraulic output valve group is provided with an oil inlet circuit, one end of which is connected to the priority valve in the electrically controlled lifting valve. The hydraulic output valve group is provided with multiple main directional valves connected to the oil inlet circuit. Each main directional valve is connected to two quick connectors for connecting to the actuator. The hydraulic output valve group is provided with multiple pilot cylinders, each of which is connected to the control end of the main directional valve. A pressure reducing valve is connected to the oil inlet circuit. Each pilot cylinder is connected to a pilot solenoid valve at both ends of its oil port. Two pilot solenoid valves are installed in parallel on the oil circuit and return oil circuit at the rear end of the pressure reducing valve.

[0006] Preferably, one end of the oil inlet circuit of the hydraulic output valve group is connected to an EF port, and a main check valve is provided at the EF port.

[0007] Preferably, a return oil check valve is also provided in the oil circuit between the front end of the switching valve and the main control valve, and the return oil check valve is set on the side facing the main control valve.

[0008] Preferably, the oil circuit of the lifting cylinder is further provided with a shut-off valve with a control handle connected to the return oil circuit of the electrically controlled lifting valve.

[0009] Preferably, in the electrically controlled lifting valve, a second relief valve is provided on the oil line at the front end of the priority valve; in the hydraulic output valve group, a first relief valve is provided on the oil inlet line.

[0010] Preferably, the return port of the main control valve is connected to the return oil circuit inside the electrically controlled lift valve through the second throttle orifice.

[0011] Preferably, the gear pump is provided with an oil suction filter at the front end and a high-pressure filter is connected to the rear end of the gear pump.

[0012] Preferably, each main directional valve is equipped with a check valve connected to the oil inlet port.

[0013] The beneficial effects of this utility model after adopting the above structure are:

[0014] 1. In this utility model, both the electrically controlled lifting valve and the hydraulic output valve group are electro-hydraulic pilot controlled, and the main valve is moved by hydraulic oil, thereby preventing the valve core from sticking or the valve from being stuck due to the thrust limitation of the electromagnet.

[0015] 2. In this utility model, the priority valve in the electrically controlled lifting valve can realize flow diversion. Under the premise of prioritizing the electrically controlled lifting, the excess flow is provided to the hydraulic output valve group. Moreover, the hydraulic output valve group is provided with EF port, which can be connected to the tractor front loading valve group or other actuators, thereby realizing the action of multiple hydraulic actuators such as the lifting valve, hydraulic output valve and tractor front loading by a single gear pump.

[0016] 3. In this utility model, both the hydraulic output valve group and the electrically controlled lifting valve have a manual operation mode. In the event of an electrical system failure, they can also be operated manually to ensure emergency needs. Attached Figure Description

[0017] Figure 1 This is a hydraulic schematic diagram of this utility model;

[0018] Figure 2 This is a schematic diagram of the hydraulic principle of the lifting device in the middle position during pressure holding.

[0019] Figure 3 This is a schematic diagram of the lifting device of this utility model when operating under proportional hydraulic pressure.

[0020] Figure 4 This is a schematic diagram of the lifting device of this utility model during proportional descent hydraulic pressure.

[0021] Figure 5 This is a hydraulic principle diagram of the hydraulic output of this utility model.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Suction filter; 2. Gear pump; 3. High-pressure filter; 4. Priority valve; 5. Proportional valve; 6. Throttling orifice one; 7. Throttling orifice two; 8. Main control valve; 9. Return check valve; 10. Switch valve; 11. Throttling orifice three; 12. Lifting cylinder; 13. Electrically controlled lifting valve; 14. Shut-off valve; 15. Relief valve one; 16. Pressure reducing valve; 17. Pilot cylinder one; 18. Pilot cylinder two; 19. Pilot cylinder three; 20. Pilot cylinder four; 21. Upper-position pilot solenoid valve one; 22. Upper-position pilot solenoid valve two; 23. Upper-position pilot solenoid valve three; 24. Upper-position pilot solenoid valve four; 25. Lower-position pilot... 26. Solenoid Valve 1; 27. Lower-position pilot solenoid valve 2; 28. Lower-position pilot solenoid valve 3; 29. ​​Lower-position pilot solenoid valve 4; 20. Check valve 1; 31. Check valve 2; 32. Check valve 3; 33. Main directional valve 1; 34. Main directional valve 2; 35. Main directional valve 3; 36. Main directional valve 4; 37. Main circuit check valve; 38. Quick coupling 1; 39. Quick coupling 2; 40. Quick coupling 3; 41. Quick coupling 4; 42. Quick coupling 5; 43. Quick coupling 6; 44. Quick coupling 7; 45. Quick coupling 8; 46. Hydraulic output valve assembly; 47. Hydraulic valve; 48. Relief valve 2. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] See Figure 1As shown, it includes an electrically controlled lift valve 13 and a hydraulic output valve assembly 46 connected thereto. The electrically controlled lift valve 13 is equipped with a priority valve 4. The upstream end of the priority valve 4 is connected to a gear pump 2 that draws oil from the oil tank. The front end of the gear pump 2 is equipped with a suction filter 1, and the rear end of the gear pump 2 is also connected to a high-pressure filter 3. The rear end of the priority valve 4 is equipped with a main control valve 8 with a manual operating handle. The downstream end of the priority valve 4 is connected to the main control valve 8 and the hydraulic output valve assembly 46 respectively. The oil line at the front end of the priority valve 4 is equipped with a relief valve 48 and a proportional valve 5. The rear end of the proportional valve 5 is connected to the main control valve 8 through a throttle orifice 6. The return port of the main control valve 8 is connected through a throttle orifice 6. Hole 2 7 is connected to the return oil circuit in the electrically controlled lifting valve 13. A hydraulic valve 47 is connected to the rear of the main control valve 8. The rear end of the hydraulic valve 47 is connected to the lifting cylinder 12. A switching valve 10 is connected to the oil circuit between the main control valve 8 and the hydraulic valve 47. A return oil check valve 9 is also provided in the oil circuit between the front end of the switching valve 10 and the main control valve 8. The return oil check valve 9 is set on the side facing the main control valve 8. The rear end of the switching valve 10 is connected to the hydraulic valve 47. The connected oil circuit is connected to the oil port of the lifting cylinder 12 through the throttle hole 3 11. A shut-off valve 14 with a control handle is also provided in the oil circuit of the lifting cylinder 12, which is connected to the return oil circuit in the electrically controlled lifting valve 13.

[0026] The hydraulic output valve assembly 46 is provided with an oil inlet, and an overflow valve 15 is provided on the oil inlet. One end of the oil inlet is connected to the priority valve 4 in the electrically controlled lift valve 13, and the other end is connected to the EF port for connecting other equipment. The EF port is provided with a main line check valve 37 to ensure that oil is supplied only when the main line pressure is sufficient. A pressure reducing valve 16 is connected to the oil inlet. The hydraulic output valve assembly 46 is provided with four main directional valves, namely main directional valve 1 33, main directional valve 2 34, main directional valve 3 35 and main directional valve 4 36.

[0027] The inlet of the main directional valve 33 is connected to the inlet line through the check valve 29. The two outlet ports of the main directional valve 33 are connected to quick connector 44 and quick connector 45 respectively. The hydraulic output valve group 46 is equipped with an upper pilot solenoid valve 21 and a lower pilot solenoid valve 25, which are installed in parallel on the oil circuit and return line of the pressure reducing valve 16. A pilot cylinder 17 is provided behind the two solenoid valves. The rear ends of the two solenoid valves are connected to the two oil ports of the pilot cylinder 17 respectively. The drive control end of the pilot cylinder 17 is connected to the control end of the main directional valve 33.

[0028] The oil inlet of the main directional valve 2 34 is connected to the oil inlet line through the check valve 2 30. The two oil outlet ports of the main directional valve 2 34 are respectively connected to quick connector 5 42 and quick connector 6 43. The hydraulic output valve group 46 is equipped with an upper pilot solenoid valve 2 22 and a lower pilot solenoid valve 2 26. The two are installed in parallel on the oil circuit and return oil circuit of the pressure reducing valve 16. A pilot cylinder 2 18 is provided behind the two solenoid valves. The rear ends of the two solenoid valves are respectively connected to the two oil ports of the pilot cylinder 2 18. The drive control end of the pilot cylinder 2 18 is connected to the control end of the main directional valve 2 34.

[0029] The inlet of the main directional valve 35 is connected to the inlet line through the check valve 31. The two outlet ports of the main directional valve 35 are respectively connected to quick connector 30 and quick connector 41. The hydraulic output valve group 46 is equipped with an upper pilot solenoid valve 323 and a lower pilot solenoid valve 327. The two are installed in parallel on the oil circuit and return line of the pressure reducing valve 16. A pilot cylinder 319 is provided behind the two solenoid valves. The rear ends of the two solenoid valves are respectively connected to the two oil ports of the pilot cylinder 319. The drive control end of the pilot cylinder 319 is connected to the control end of the main directional valve 35.

[0030] The inlet of the main directional valve 36 is connected to the inlet line through the check valve 32. The two outlet ports of the main directional valve 36 are connected to quick connector 38 and quick connector 39 respectively. The hydraulic output valve group 46 is equipped with an upper pilot solenoid valve 24 and a lower pilot solenoid valve 28, which are installed in parallel on the oil circuit and return line of the pressure reducing valve 16. A pilot cylinder 20 is located behind the two solenoid valves. The rear ends of the two solenoid valves are connected to the two oil ports of the pilot cylinder 20 respectively. The drive control end of the pilot cylinder 20 is connected to the control end of the main directional valve 36.

[0031] The principle of maintaining pressure in the middle position of the lifting cylinder 12 during use:

[0032] like Figure 2 As shown, at this time, proportional valve 5 and switching valve 10 are not energized. The control oil on the left side of priority valve 4 passes through the main control valve 8 in the middle position, and then through the throttle orifice 6, and is discharged back to the oil tank from the position of proportional valve 5. Therefore, there is no pressure on the left side of priority valve 4 at this time. The pumped pressure oil acts on the right side of priority valve 4. The pressure on the right side overcomes the spring force on the left side of priority valve 4. Therefore, priority valve 4 is in the right position at this time. At this time, gear pump 2 pumps out oil, which is filtered by suction filter 1 and high pressure filter 3, and then sent from the right position of priority valve 4 through the EF port of the electric lift valve 13 into the hydraulic output valve group 46, or directly discharged back to the oil tank, with the middle position unloaded.

[0033] During use, the principle behind the lifting cylinder 12's function of raising the lift proportionally is as follows:

[0034] like Figure 3 As shown in the diagram, for ease of understanding, a transition position is drawn in proportional valve 5. The transition position is an A-type bridge. The pumped pressure oil flows back to the oil tank through the two transition positions (adjustable throttle ports) of proportional valve 5. Therefore, the current of proportional valve 5 can change the pressure at the left end of main control valve 8, thereby allowing main control valve 8 to switch between the rising and falling positions. The oil inlet of main control valve 8 acts on the right end of priority valve 4 through the control oil circuit, while the oil outlet acts on the left end of priority valve 4 through the shuttle valve in the rising position of the valve. This ensures that the pressure difference between the inlet and outlet of main control valve 8 is the pressure set by the spring lock on the left side of priority valve 4. Therefore, the lifting speed of lifting cylinder 12 is proportionally adjustable. In addition, the main pressure of the rising oil circuit will be greater than the control pressure at the left end of main control valve 8, thus the water in main control valve 8... The shuttle valve is used for pressure isolation to prevent pressure crosstalk between the main oil circuit and the control oil circuit. During operation, the proportional valve 5 is energized, the gear pump 2 starts pumping oil, which is filtered and sent to the neutral position of the priority valve 4, then to the rising position of the main control valve 8, then to the left position of the hydraulic valve 47, and then to the lower chamber of the lifting cylinder 12, causing the lifting cylinder 12 to rise. The excess oil pumped out by the gear pump 2 is sent to the hydraulic output valve group 46 through the priority valve 4, and then discharged back to the oil tank. After the piston rod of the lifting cylinder 12 extends to the end position, the priority valve 44 is in the left position, the system is depressurized, and then the relief valve 2 48 opens to ensure the installation of the hydraulic system. In addition, in the event of an electrical fault, the main control valve 8 can be manually switched between the rising position, the transition position, the falling position, and the neutral position.

[0035] During use, the principle behind the lifting cylinder 12's function of lowering the lift's proportional section is as follows:

[0036] like Figure 4 When the switching valve 10 is energized, it operates in its right position. By adjusting the current of the proportional valve 5, the main control valve 8 is positioned in the lowering position. The oil in the lifting cylinder 12 flows into the switching valve 10 through the throttle orifice 11, and then flows through the return check valve 9 to the main control valve 8 in the lowering position, and then flows back to the oil tank, thereby lowering the lifting cylinder 12. The inlet pressure of the main control valve 8 is the load pressure, and the outlet is the oil tank at zero pressure. During this process, adjusting the current of the proportional valve 5 can adjust the size of the lowering opening of the main control valve 8, thereby adjusting the flow rate of the hydraulic oil and controlling the lowering speed of the lifting cylinder 12. In the event of an electrical fault, the electronically controlled system cannot complete the lowering. In this case, the shut-off valve 14 can be opened, and the oil in the lower chamber of the cylinder can be directly connected to the return oil circuit, realizing the lowering action of the lifting cylinder 12 in an emergency. During the lowering of the lifting cylinder 12, the oil sucked by the gear pump 2 will be directly discharged back to the oil tank through the priority valve 4.

[0037] During tractor transport, under the shock-absorbing platform, the switching valve 10 is not energized, while the proportional valve 5 is energized. The outlet pressure of the main control valve 8 and the load pressure of the hydraulic cylinder act on the right end face of the hydraulic valve 47. However, due to the small area of ​​the hydraulic cylinder's load pressure, under normal conditions, the load pressure of the hydraulic cylinder is insufficient to push the hydraulic valve 47 to the right position. During transport, due to the bumps of the implement, a momentary high pressure peak occurs in the lifting cylinder 12, pushing the hydraulic valve 47 to the right position. At this time, the oil in the lifting cylinder 12 passes through the right-position hydraulic valve 47 and then through the descending main control valve 8 into the oil tank, thereby eliminating the pressure peak caused by the bumps of the implement. An angle sensor is installed on the rocker arm of the tractor lift to sense the descent of the lifting cylinder 12 and feeds it back to the controller. The controller then adjusts the system to the rising position to compensate for the static settlement caused by the bumps.

[0038] The operating principle of the hydraulic output valve assembly 46 during use:

[0039] like Figure 5 The hydraulic output mainly provides hydraulic power to agricultural machinery. The relief valve 15 acts as a safety valve to ensure system safety. The pressure reducing valve 16 and the main line check valve 37 provide pilot switching pressure for multiple main directional valves. Taking the main directional valve 33 as an example: First, the pressure valve is set to 4 MPa, and the main line check valve 37 is set to 2 MPa to ensure stable pilot switching pressure for the main directional valve 33. Then, the lower-position pilot solenoid valve 25 is energized, and the pilot cylinder 17 extends, enabling the main directional valve 33 to operate in its lower position. Specifically, the pilot oil circuit is drawn by the gear pump 2. After the hydraulic oil is pumped, it is sent to the electrically controlled lifting valve 13, and then through the pressure reducing valve 16 to enter the lower pilot solenoid valve 25, causing the pilot cylinder 17 to extend. The main oil circuit is where the oil drawn by the gear pump 2 passes through the electrically controlled lifting valve 13, and then through the check valve 29 to enter the lower main directional valve 33, and is sent out from the quick connector 44. At this time, the return oil circuit is through the quick connector 45, where the oil flows in, enters the lower main directional valve 33, and is discharged back into the oil tank. Thus, the double-acting actuator connected by quick connectors 44 and 45 descends, and vice versa.

[0040] The installation, connection, or setting methods of the components not detailed above are all common mechanical methods, and the specific structure, model, and coefficient indicators of all their components are their own technologies. As long as they can achieve their beneficial effects, they can be implemented, so they will not be elaborated further.

[0041] It should be understood that the above-described specific embodiments of this utility model are merely illustrative or explanatory of the principles of this utility model and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of this utility model should be included within the protection scope of this utility model. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A tractor pilot hydraulic control hydraulic system comprising an electrically controlled poppet valve (13) and a hydraulic output valve group (46) connected thereto, characterized in that: The electric lifting valve (13) is equipped with a priority valve (4). The upstream end of the priority valve (4) is connected to a gear pump (2) that draws oil into the oil tank. The rear end of the priority valve (4) is equipped with a main control valve (8). The downstream end of the priority valve (4) is connected to the main control valve (8) and the hydraulic output valve group (46) respectively. The oil circuit at the front end of the priority valve (4) is also connected to a proportional valve (5). The rear end of the proportional valve (5) is connected to the main control valve (8) through a throttle hole (6). The rear end of the main control valve (8) is connected to a hydraulic valve (47). The rear end of the hydraulic valve (47) is connected to the lifting cylinder (12). The oil circuit between the main control valve (8) and the hydraulic valve (47) is connected to a switch valve (10). The rear end of the switch valve (10) is connected to the hydraulic valve (47). The connected oil circuit is connected to the oil port of the lifting cylinder (12) through a throttle hole (11).

2. A pilot hydraulic control hydraulic system for a tractor as claimed in claim 1, wherein: The hydraulic output valve group (46) is provided with an oil inlet. One end of the oil inlet is connected to the priority valve (4) in the electrically controlled lifting valve (13). The hydraulic output valve group (46) is provided with multiple main directional valves connected to the oil inlet. Each main directional valve is connected to two quick connectors for connecting the actuator. The hydraulic output valve group (46) is provided with multiple pilot cylinders. Each pilot cylinder is connected to the control end of the main directional valve. A pressure reducing valve (16) is connected to the oil inlet. Each pilot cylinder is connected to a pilot solenoid valve at both ends of the oil port. Two pilot solenoid valves are installed in parallel on the oil circuit and return oil circuit at the rear end of the pressure reducing valve (16).

3. A pilot hydraulic control hydraulic system for a tractor as claimed in claim 2, wherein: The hydraulic output valve group (46) has an EF port at one end in its oil inlet circuit, and a main check valve (37) is provided at the EF port.

4. A pilot hydraulic control hydraulic system for a tractor as claimed in claim 1, wherein: A return oil check valve (9) is also provided in the oil circuit between the front end of the switching valve (10) and the main control valve (8), and the return oil check valve (9) is set on the side facing the main control valve (8).

5. A pilot hydraulic control hydraulic system for a tractor as claimed in claim 1, wherein: The oil circuit of the lifting cylinder (12) is also equipped with a shut-off valve (14) with a control handle connected to the return oil circuit of the electrically controlled lifting valve (13).

6. A pilot hydraulic control hydraulic system for a tractor as claimed in claim 2, wherein: In the electrically controlled lifting valve (13), a relief valve 2 (48) is provided on the oil line at the front end of the priority valve (4); in the hydraulic output valve group (46), a relief valve 1 (15) is provided on the oil inlet line.

7. A pilot hydraulic control hydraulic system for a tractor as claimed in claim 1, wherein: The return port of the main control valve (8) is connected to the return oil path inside the electrically controlled lift valve (13) through the throttle hole two (7).

8. A pilot hydraulic control hydraulic system for a tractor as claimed in claim 1, wherein: The gear pump (2) is equipped with an oil suction filter (1) at the front end and a high pressure filter (3) at the rear end.

9. A pilot hydraulic control hydraulic system for a tractor as claimed in claim 2, wherein: Each main directional valve has a check valve connected to the oil port that is connected to the oil inlet.

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