Multifunctional lifting hydraulic system of tractor

Abstract

A multifunctional lifting hydraulic system of a tractor comprises an electric proportional lifting unit and a manual lifting pressure lifting unit which can work independently, a multi-way valve assembly integrates a first multi-way valve, a zero-leakage valve and a single-double-action switching valve, the zero-leakage valve is in linkage with a valve element of the first multi-way valve, and the control precision and efficiency of the system are improved; and one end of the single-double-acting switching valve is communicated with the upper cavity of the oil cylinder, and the other end is communicated with the hydraulic oil tank oil return path. Under the conventional working condition, oil is supplied to the oil cylinder through the electric proportional lifting valve group; and oil is supplied to the oil cylinder and returned to the oil cylinder through the multi-way valve assembly in case of emergency and high-pressure work, so that the reliability and the stability of the system are improved. The multi-way valve assembly integrates a single-action switch valve and a double-action switch valve, switching of the high-pressure function and the non-high-pressure function is achieved by adjusting opening and closing of the single-action switch valve and the double-action switch valve, and pipelines contained in the high-pressure lifting device can be greatly simplified.

Description

Technical Field

[0001] The invention relates to the field of hydraulic technology, and in particular to a multifunctional lifting hydraulic system for a tractor. Background Art

[0002] The tractor rear suspension system can accurately control the flow direction and flow rate of hydraulic oil through the control of the electric proportional lifting valve group, thereby realizing the motion control of the actuator. When the existing hydraulic system faces a failure or abnormal situation of the electronic control part, it often causes the paralysis of the entire system, resulting in production interruption and safety hazards. Application number 2024108740648 discloses a hydraulic system with mechanical backup. Under normal circumstances, the actuator is accurately and efficiently controlled by the electric proportional valve group; when an abnormal situation occurs in the system, the switching valve group is manually switched to the working position of the multi-way valve group, which effectively avoids the system paralysis caused by electronic control failure, improves the reliability and stability of the system, and can reduce the occurrence of production interruptions and safety accidents. When an abnormal situation occurs or a strong pressure drop is required, the hydraulic system needs to manually operate the switching valve group to the working position of the multi-way valve group, which is inefficient. Utility Model Content

[0003] The invention provides a multifunctional lifting hydraulic system for a tractor. The system can directly switch to a multi-way valve group to work when an electronic control part fails or strong pressure is required, without manual operation of switching the valve group, thereby improving the efficiency of the system.

[0004] Specifically, a multifunctional lifting hydraulic system for a tractor includes: an oil tank, an electric proportional lifting valve group, a multi-way valve assembly, and an oil cylinder.

[0005] The multi-way valve assembly integrates a first multi-way valve, a zero leakage valve, and a single- and double-acting switching valve, and the zero leakage valve is linked to the valve core of the first multi-way valve;

[0006] One end of the single-acting and double-acting switching valve is connected to the upper chamber of the oil cylinder, and the other end is connected to the oil return line of the hydraulic oil tank;

[0007] The electric proportional lift valve group is superimposed on the multi-way valve assembly, and the oil circuit between the electric proportional lift valve group and the multi-way valve assembly is connected with a pressure compensation valve;

[0008] Under normal working conditions, oil is supplied to the cylinder through the electric proportional lift valve group; in emergency situations and high-pressure operation, oil is supplied to and returned from the cylinder through the multi-way valve assembly.

[0009] The single-acting and double-acting switch valve is manually closed when the multi-way valve assembly works in the strong pressure drop position, and is opened when the multi-way valve assembly is in other working positions.

[0010] In one embodiment, the electric proportional lift valve group includes a proportional lift valve connected between the oil inlet P1 and the rodless chamber of the cylinder, a proportional down valve connected to the return oil circuit, and a one-way valve is connected to the oil circuit between the proportional lift valve and the proportional down valve.

[0011] Furthermore, a one-way valve is connected to the oil circuit between the pressure compensation valve and the multi-way valve assembly.

[0012] Furthermore, the first multi-way valve is a four-position mechanical valve, which is used for lifting, high-pressure lowering, floating, and neutral positions of the machine respectively. The multi-way valve assembly also includes at least one mechanical reversing valve, which is used for other backup functions of the machine, such as deployment and recovery of the machine, etc. The mechanical reversing valve integrates a single-acting and double-acting switch valve, one end of which is connected to the hydraulic actuator, and the other end is connected to the return oil circuit of the hydraulic oil tank.

[0013] Furthermore, an overflow valve is connected between the oil inlet P1 and the oil return port T1, and the overflow valve is used to limit the maximum pressure of the hydraulic main circuit.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects:

[0015] A zero leakage valve is integrated in the multi-way valve assembly. The valve core of the zero leakage valve is linked with the valve core of the multi-way valve to ensure the sealing of the hydraulic circuit of the multi-way valve and improve the control accuracy and efficiency of the system.

[0016] The hydraulic system includes an electric proportional lifting link and a manual high-pressure lifting link that can work independently. When an abnormal situation occurs in the system, the manual high-pressure lifting link can continue to work, thereby improving the reliability and stability of the system.

[0017] The multi-way valve assembly integrates single and double-acting switch valves. When the multi-way valve assembly works in the high-pressure lowering position, the single and double-acting switch valves are closed to achieve single-acting output; in other working positions, the single and double-acting switch valves are opened to achieve the conversion of hydraulic single-acting output to hydraulic double-acting output. The switching of high-pressure-non-high-pressure functions is achieved by adjusting the opening and closing of the single and double-acting switch valves, which can greatly simplify the piping contained in the high-pressure lifting device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to further understand the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0019] Figure 1 , which is the schematic diagram of the tractor's multifunctional lifting hydraulic system. DETAILED DESCRIPTION

[0020] In order to make the technical solutions and advantages of the present invention clearer, the following will be combined with the accompanying drawings to clearly and completely describe the implementation methods of the present invention. Obviously, the described embodiments are only some embodiments of the present invention. Based on the described embodiments, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish the relationship between multiple identical elements. In this application, "left", "right", "upper" and "lower" are only used to facilitate the description of the positional relationship shown in the drawings and should not be understood as limitations on the present invention. The terms "connected" and "connected" in the present invention should be understood in a broad sense.

[0022] Combination Figure 1 The multifunctional lifting hydraulic system of the tractor includes an oil pump 6, an oil tank, an oil cylinder 8, an electric proportional lifting link 1, a manual lifting strong pressure link 2, and an electric proportional lifting valve group including a proportional lifting valve 11, a proportional lowering valve 12, and a one-way valve 13. The proportional lifting valve 11 is connected to the oil pump outlet P1 through one end of an oil pipe, and one end of the proportional lowering valve 12 is connected to the oil return circuit R1. The oil circuit between the proportional lifting valve 11 and the proportional lowering valve 12 is connected with a one-way valve 13, and the A end of the electric proportional lifting valve group is connected to the rodless chamber of the oil cylinder 8 through an oil pipe.

[0023] Under normal working conditions, the first multi-way valve 26 does not work, and the electric proportional lifting valve group works to supply oil to the rodless chamber of the cylinder. When the machine is lifted, the proportional solenoid DT2 is energized, and the hydraulic oil at the oil inlet P1 passes through the proportional lifting valve 11 and the one-way valve 13 to the rodless chamber of the cylinder. The cylinder is extended and retracted to drive the machine to rise, and the oil in the rod chamber of the cylinder returns to the T1 port of the oil tank from the B1 end and the single and double acting switch valve; when the machine is lowered, the proportional solenoid DT1 is energized, the one-way valve 13 is reversely blocked, and the hydraulic oil returns to the return oil port R1 from the rodless chamber of the cylinder and the proportional lowering valve 12.

[0024] The manual lifting strong pressure link 2 includes a multi-way valve assembly, which integrates a first multi-way valve 26, a zero leakage valve, and a single-double-acting switching valve 27. The zero leakage valve is linked to the first multi-way valve spool to ensure the sealing of the multi-way valve hydraulic circuit and improve the control accuracy and efficiency of the system. In this solution, the upper chamber of the oil cylinder is a rod chamber, and the lower chamber is a rodless chamber. On the basis of ensuring the conversion function of strong pressure-non-strong pressure, the single-double-acting switching valve 27 is integrated into the multi-way valve assembly in consideration of simplifying the pipeline. One end of the single-double-acting switching valve 27 is connected to the upper chamber of the oil cylinder, and the other end is connected to the return oil circuit of the hydraulic oil tank. By opening and closing the single-double-acting switching valve, the conversion from strong pressure to non-strong pressure can be realized, and at the same time, the pipeline of the strong pressure lifting device is greatly simplified.

[0025] In this scheme, the first multi-way valve 26 is a four-position mechanical valve, which is used for the lifting, high-pressure lowering, floating and middle positions of the machine respectively. When the four-position mechanical valve works in the lifting, floating and middle positions, the single-double-acting switching valve 27 is in the open state, and double-acting hydraulic output is present; when working in the high-pressure lowering position, the single-double-acting switching valve is closed to realize single-acting hydraulic output. The conversion from hydraulic double-acting output to hydraulic single-acting output is realized by opening / closing the single-double-acting switching valve. The switching between high-pressure and non-high-pressure functions can be realized by adjusting the opening and closing of the single-double-acting switch valve.

[0026] According to the actual working conditions, the multi-way valve assembly can also add one or more mechanical reversing valve groups, such as the second mechanical reversing valve group 28 and the third mechanical reversing valve group 29 described in the attached drawings, which are used for other backup functions of the machine, such as the deployment and recovery of the machine, etc. The second mechanical reversing valve group and the third mechanical reversing valve group integrate a single-acting and double-acting switching valve 27. One end of the single-acting and double-acting switching valve 27 is connected to the hydraulic actuator, and the other end is connected to the hydraulic return oil circuit. When the mechanical reversing valve needs a strong pressure output, this valve is closed to realize the conversion of the double-acting hydraulic output to the single-acting hydraulic output.

[0027] In this solution, the oil circuit between the electric proportional lift valve group and the multi-way valve assembly is connected with a pressure compensation valve 14, and the oil circuit between the pressure compensation valve and the multi-way valve assembly is connected with a check valve 15. When the system is unloaded or external factors such as temperature changes cause pressure shocks and fluctuations, the hydraulic oil enters the pressure compensation valve, the hydraulic pressure overcomes the spring force to push the valve core to move, and the hydraulic oil flows through the check valve 15 back to the P3 port to the oil tank.

[0028] In actual application, when the electronic control part of the electric proportional lifting link 1 fails or strong pressure is required, switching to the manual lifting strong pressure link 2 can reduce production interruptions and improve system reliability. When the multi-way valve assembly is working, the zero leakage valve moves with the multi-way valve valve core to ensure the sealing of the multi-way valve hydraulic circuit and improve efficiency. When the multi-way valve assembly works in the lifting position, the zero-leakage valve is opened at the same time, and the hydraulic oil enters the pressure compensation valve from the P1 port. The liquid pressure overcomes the spring force to push the valve core to move. The hydraulic oil passes through the one-way valve 15 to the multi-way valve lifting position 26 and the zero-leakage valve and then enters the rodless chamber of the cylinder 8. At this time, the single-acting and double-acting switch valves are in the open state, and the hydraulic oil in the rod chamber of the cylinder returns to the T1 port through the double-acting output; when the machine needs to work under strong pressure, the single-acting and double-acting switch valves are closed, and the multi-way valve assembly is manually operated to work in the strong pressure descending position. At the same time, the zero-leakage valve is opened, and the oil from the oil pump enters the rod chamber of the cylinder from the B1 port through the pressure compensation valve 14 and the one-way valve 15. The oil in the rodless chamber of the cylinder flows through the multi-way valve descending position back to the T1 port. Since the single-acting and double-acting switch valve is closed, the conversion from hydraulic double-acting output to hydraulic single-acting output is realized, and the switching of non-strong pressure-strong pressure function is realized by adjusting the opening and closing of the single-acting and double-acting switch valves.

[0029] In this solution, an overflow valve is connected between the hydraulic system oil inlet P1 and the oil return port T1. When the total system pressure exceeds the threshold, the overflow valve opens and the excess hydraulic oil flows back to the T1 port to prevent the system pressure from being too high and maintain pressure stability.

[0030] The hydraulic system includes an electric proportional lifting link and a manual lifting strong pressure link that can work independently. The electric proportional lifting link realizes a smooth and accurate lifting process of the machine and reduces the work intensity. When the system is abnormal or needs to be forced to drop, it switches to the manual lifting strong pressure link. The multi-way valve assembly is integrated with a zero leakage valve. The valve core of the zero leakage valve is linked with the valve core of the first multi-way valve to ensure the sealing of the multi-way valve hydraulic circuit and improve the control accuracy and efficiency of the system. The multi-way valve assembly integrates a single and double-acting switch valve, and the switching of the strong pressure-non-strong pressure function is realized by adjusting the opening and closing of the single and double-acting switch valve. The present invention optimizes the structure of the hydraulic control system and uses different valve switches to realize the conversion between multiple functions, simplifies the pipeline of the hydraulic system, and improves the reliability of the system and the convenience of operation.

Claims

1. A multifunctional lifting hydraulic system for a tractor, comprising: Oil tank, electric proportional lifting valve group, multi-way valve assembly, oil cylinder, characterized in that the multi-way valve assembly integrates a first multi-way valve, a zero leakage valve, and a single-double-acting switching valve, and the zero leakage valve is linked with the valve core of the first multi-way valve; One end of the single-acting and double-acting switching valve is connected to the upper chamber of the oil cylinder, and the other end is connected to the oil return line of the hydraulic oil tank; The electric proportional lift valve group is superimposed on the multi-way valve assembly, and the oil circuit between the electric proportional lift valve group and the multi-way valve assembly is connected with a pressure compensation valve; Under normal working conditions, oil is supplied to the cylinder through the electric proportional lift valve group; in emergency situations and high-pressure operation, oil is supplied to and returned from the cylinder through the multi-way valve assembly.

2. The multifunctional lifting hydraulic system for tractors according to claim 1, characterized in that: The single-acting and double-acting switch valve is manually closed when the multi-way valve assembly works in the strong pressure drop position, and is opened when the multi-way valve assembly is in other working positions.

3. The multifunctional lifting hydraulic system for tractors according to claim 1, characterized in that: The electric proportional lift valve group includes a proportional lift valve connected between the oil inlet P1 and the rodless chamber of the oil cylinder, and a proportional drop valve connected to the oil return line.

4. The multifunctional lifting hydraulic system for tractors according to claim 3, characterized in that: A one-way valve is connected to the oil circuit between the proportional lift valve and the proportional drop valve.

5. The multifunctional lifting hydraulic system for tractors according to claim 1, characterized in that: The oil circuit between the pressure compensating valve and the multi-way valve assembly is connected with a one-way valve.

6. The multifunctional lifting hydraulic system for tractors according to claim 1, characterized in that: The first multi-way valve is a four-position mechanical valve, which is used for lifting, high-pressure lowering, floating and neutral positions of the machine respectively.

7. The multifunctional lifting hydraulic system for tractors according to claim 1, characterized in that: The multi-way valve assembly also includes at least one mechanical reversing valve for other backup functions of the machine.

8. The multifunctional lifting hydraulic system for tractors according to claim 7, characterized in that: The mechanical reversing valve integrates a single-acting and double-acting switch valve, one end of the single-acting and double-acting switch valve is connected to the hydraulic actuator, and the other end is connected to the oil return line of the hydraulic oil tank.

9. The multifunctional lifting hydraulic system for tractors according to claim 1, characterized in that: The hydraulic system further includes an overflow valve connected between the oil inlet P1 and the oil return port T1 for limiting the maximum pressure of the hydraulic main circuit.

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