Hydraulic control system of asymmetric hydraulic cylinder

Abstract

The invention provides a hydraulic control system of an asymmetric hydraulic cylinder, and relates to the technical field of hydraulic control, the hydraulic control system comprises a bidirectional hydraulic pump, a hydraulic motor and an energy accumulator, the bidirectional hydraulic pump is in transmission connection with a first servo motor, and a first oil port and a second oil port of the bidirectional hydraulic pump are connected with a rod cavity and a rodless cavity through a first oil way and a second oil way respectively; a first one-way valve is arranged between the second oil port and the rodless cavity; the hydraulic motor is in transmission connection with the generator which is connected with the electric energy storage unit. The hydraulic motor is connected with the first one-way valve in parallel; the energy accumulator communicates with the first oil way and the second oil way through a second one-way valve and a third one-way valve correspondingly. Four-quadrant seamless switching can be achieved, the structure is simpler, the complexity of a pipeline in a hydraulic system is remarkably reduced, energy collection can be conducted on oil discharged by a rodless cavity, and energy consumption is further reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic control, and in particular to a hydraulic control system of an asymmetric hydraulic cylinder. Background Art

[0002] With the rapid development of industrial automation and mechanical engineering, the demand for hydraulic systems is growing. In heavy-duty construction machinery such as loaders and excavators, the performance of the hydraulic system directly impacts the equipment's operating efficiency and energy consumption. Traditional hydraulic systems, particularly those in excavators, typically utilize centralized hydraulic pumps and multi-way valve control. While this design is mature, it suffers from the complex control system caused by the multiple valves controlling the hydraulic system, resulting in poor dynamic response and low energy efficiency.

[0003] Therefore, it is necessary to improve the traditional hydraulic control system to solve the above technical problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a hydraulic control system for an asymmetric hydraulic cylinder to solve the problems existing in the above-mentioned prior art, which can realize seamless switching of four quadrants, has a simpler structure, significantly reduces the complexity of the pipelines in the hydraulic system, and can collect energy from the oil discharged from the rodless cavity to further reduce energy consumption.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A hydraulic control system for an asymmetric hydraulic cylinder includes a bidirectional hydraulic pump, a hydraulic motor and an accumulator, wherein the bidirectional hydraulic pump is transmission-connected to a first servo motor, and the first oil port and the second oil port of the bidirectional hydraulic pump are connected to the rod chamber and the rodless chamber of the asymmetric hydraulic cylinder through a first oil circuit and a second oil circuit respectively; a first one-way valve is arranged between the second oil port and the rodless chamber; the hydraulic motor is transmission-connected to a generator, and the generator is connected to an electric energy storage unit; the hydraulic motor is arranged in parallel with the first one-way valve; the accumulator is connected to the first oil circuit and the second oil circuit through a second one-way valve and a third one-way valve respectively; a first overflow valve and a second overflow valve are respectively arranged between the first oil circuit and the accumulator, and between the second oil circuit and the accumulator, the first overflow valve and the second one-way valve are arranged in parallel, and the second overflow valve and the third one-way valve are arranged in parallel.

[0007] As one embodiment, the second one-way valve and / or the third one-way valve are hydraulically controlled one-way valves, the hydraulic control line of the second one-way valve is connected to the first oil circuit, and the hydraulic control line of the third one-way valve is connected to the second oil circuit.

[0008] As an embodiment, a first shut-off valve connected in parallel with the asymmetric hydraulic cylinder is provided between the first oil circuit and the second oil circuit.

[0009] As an embodiment, the invention further includes a second shut-off valve and a proportional flow control valve arranged in parallel, wherein the second shut-off valve and the proportional flow control valve are both connected in series with the hydraulic motor.

[0010] As an embodiment, it further includes a one-way hydraulic pump transmission-connected to the second servo motor, wherein the oil inlet of the one-way hydraulic pump is connected to the oil tank, and the oil outlet is connected to the first oil circuit.

[0011] As an embodiment, a filter and a fourth one-way valve are sequentially provided between the oil outlet of the one-way hydraulic pump and the first oil circuit.

[0012] As one embodiment, it also includes a first motor driver, a second motor driver and a third motor driver that are communicatively connected to the first servo motor, the generator and the second servo motor respectively, and the first motor driver, the second motor driver and the third motor driver are all communicatively connected to the controller and the electric energy storage unit.

[0013] As an embodiment, it further includes a lighting device and a cooling fan that are communicatively connected to the electric energy storage unit.

[0014] As one embodiment, it also includes a first pressure sensor for measuring the pressure of the first oil port, a second pressure sensor for measuring the pressure of the rod chamber, a third pressure sensor for measuring the pressure of the rodless chamber, a database and a differential analyzer. The first pressure sensor, the second pressure sensor, the third pressure sensor and the differential analyzer are all communicated with the database, the differential analyzer communicates with the database and is connected to the controller. The database is used to store normal working values under different working conditions and solutions to abnormal operation of the hydraulic control system. The controller is used to control the actions of the first servo motor, the generator and the second servo motor under different abnormal working conditions according to the solutions in the database.

[0015] As one embodiment, it also includes a first vibration sensor, a second vibration sensor, a third vibration sensor and a fourth vibration sensor that are communicatively connected to the database, and the first vibration sensor, the second vibration sensor, the third vibration sensor and the fourth vibration sensor are used to measure the vibration amplitude of the piston rod in the asymmetric hydraulic oil, the vibration amplitude of the hydraulic motor, the vibration amplitude of the bidirectional hydraulic pump and the vibration amplitude of the unidirectional hydraulic pump, respectively.

[0016] Compared with the prior art, the present invention has the following technical effects:

[0017] By providing a bi-directional servo motor and a bi-directional hydraulic pump, the present invention can drive the hydraulic fluid to flow in both directions, match the load conditions, achieve seamless switching in four quadrants, with a simpler structure, significantly reducing the complexity of the pipelines in the hydraulic system. Moreover, the present invention is provided with a hydraulic motor and a generator in parallel with the first one-way valve on the second oil path, which can collect the energy of the hydraulic fluid discharged from the rodless cavity. At the same time, under the condition of a smooth load, the system can suspend the energy supply of the main pump and directly use the kinetic energy of the load to drive the hydraulic motor to generate electricity, further reducing energy consumption.

[0018] Other technical effects that the present invention can achieve compared with the prior art are described in the specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the following-described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 It is a schematic diagram of the principle of a hydraulic control system for an asymmetric hydraulic cylinder in an embodiment of the present invention;

[0021] Figure 2 It is a schematic diagram of the principle applied to the working condition with little accumulator compensation flow in an embodiment of the present invention;

[0022] Figure 3 It is a schematic diagram of the principle applied to the working condition of equipment with little energy recovery in an embodiment of the present invention;

[0023] Figure 4 It is a schematic diagram of energy transfer in an embodiment of the present invention;

[0024] Figure 5 [[ID=3]]It is a schematic diagram of the principle of a hydraulic control system with an intelligent cloud diagnosis and collaborative decision-making module in an embodiment of the present invention;

[0025] Figure 6 It is a schematic diagram of the principle of the intelligent cloud diagnosis and collaborative decision-making module in an embodiment of the present invention.

[0026] DESCRIPTION OF THE REFERENCE NUMERALS:

[0027] 1. Bi-directional hydraulic pump; 2. First servo motor; 3. Asymmetric hydraulic cylinder; 4. Hydraulic motor; 5. Generator; 6. Electrical energy storage unit; 7. First check valve; 8. Second check valve; 9. Third check valve; 10. Accumulator; 11. First relief valve; 12. Second relief valve; 13. First stop valve; 14. Second stop valve; 15. Proportional flow control valve; 16. Rotational speed sensor; 17. Unidirectional hydraulic pump; 18. Second servo motor; 19. Filter; 20. Fourth check valve; 21. Third relief valve; 22. Controller; 23. First motor driver; 24. Second motor driver; 25. Third motor driver; 26. Lighting equipment; 27. Cooling fan; 28. First pressure sensor; 29. Second pressure sensor; 30. Third pressure sensor; 31. First vibration sensor; 32. Second vibration sensor; 33. Third vibration sensor; 34. Database; 35. Differential analyzer. Detailed implementation manners

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] The purpose of the present invention is to provide a hydraulic control system for an asymmetric hydraulic cylinder to solve the problems existing in the prior art, which can achieve seamless four-quadrant switching, has a simpler structure, significantly reduces the complexity of the pipelines in the hydraulic system, and can collect the energy of the oil discharged from the rodless cavity, further reducing energy consumption.

[0030] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0031] As Figures 1 to 6As shown in the figure, a hydraulic control system for an asymmetric hydraulic cylinder 3 includes a bidirectional hydraulic pump 1, a hydraulic motor 4, and an accumulator 10. The bidirectional hydraulic pump 1 is drivingly connected to a first servo motor 2. The first servo motor 2 is a bidirectional variable-speed servo motor. The first oil port and the second oil port of the bidirectional hydraulic pump 1 are respectively connected to the rodless chamber and the rod chamber of the asymmetric hydraulic cylinder 3 through a first oil circuit and a second oil circuit. A first one-way valve 7 is provided between the second oil port and the rodless chamber, allowing the oil to flow unidirectionally from the second oil port to the rodless chamber. The hydraulic motor 4 is drivingly connected to a generator 5. The generator 5 is connected to an electrical energy storage unit 6. When the hydraulic motor 4 rotates, it can drive the generator 5 to rotate and generate electricity, and store the electrical energy in the electrical energy storage unit 6. The hydraulic motor 4 is arranged in parallel with the first one-way valve 7. The accumulator 10 is respectively communicated with the first oil circuit and the second oil circuit through a second one-way valve 8 and a third one-way valve 9. A first overflow valve 11 and a second overflow valve 12 are respectively provided between the first oil circuit and the accumulator 10, and between the second oil circuit and the accumulator 10. The first overflow valve 11 is arranged in parallel with the second one-way valve 8, and the second overflow valve 12 is arranged in parallel with the third one-way valve 9.

[0032] Taking Figure 1 as an example, when the piston rod of the asymmetric hydraulic cylinder 3 extends upward and the load force is downward, that is, in the impedance extension condition of the first quadrant movement in the four-quadrant working condition (in this embodiment, the abscissa of the four-quadrant working condition of the asymmetric hydraulic cylinder 3 is the direction of the load force, the downward load force is positive, the ordinate is the direction of the piston rod speed or displacement direction, and the upward extension is positive), the rodless chamber of the asymmetric hydraulic cylinder 3 is the high-pressure chamber, and the rod chamber is the low-pressure chamber. When the piston rod of the asymmetric hydraulic cylinder 3 extends upward, the electrical energy storage unit 6 supplies power to the first servo motor 2 and the bidirectional hydraulic pump 1, so that the bidirectional hydraulic pump 1 rotates forward to make the oil flow through the first one-way valve 7 to the rodless chamber of the asymmetric hydraulic cylinder 3 to push the piston rod upward. At the same time, when supplying oil to the rodless chamber of the asymmetric hydraulic cylinder 3, the accumulator 10 will supply oil to the oil circuit through the second one-way valve 8 to compensate for the asymmetric flow of the asymmetric hydraulic cylinder 3. The reason for supplying oil through the second one-way valve 8 instead of the third one-way valve 9 is that the pressure of the second oil circuit is higher and the pressure of the first oil circuit is lower, and the accumulator 10 can only supply oil to the oil circuit with lower pressure. The accumulator 10 is a commonly used oil replenishing device in the art, and its specific structure and working principle are well known to those skilled in the art, so they will not be described in detail in this embodiment.

[0033] When the piston rod of the asymmetric hydraulic cylinder 3 extends upward and the load force is upward, that is, in the over-extension condition of the second quadrant movement in the four-quadrant working condition, the rod chamber of the asymmetric hydraulic cylinder 3 is the high-pressure chamber, and the rodless chamber is the low-pressure chamber. When the piston rod of the asymmetric hydraulic cylinder 3 extends upward, at this time, under the action of the load force, the oil will flow from the rod chamber through the bidirectional hydraulic pump 1 into the rodless chamber to make the piston rod extend upward. At this time, the electric energy storage unit 6 can temporarily stop supplying electric energy to the bidirectional hydraulic pump 1 to achieve energy-saving effect. At the same time, the accumulator 10 will supply oil to the circuit from the third one-way valve 9 to compensate for the asymmetric flow of the asymmetric hydraulic cylinder 3.

[0034] When the piston rod of the asymmetric hydraulic cylinder 3 retracts downward and the load force is upward, that is, in the impedance retraction condition of the third quadrant movement in the four-quadrant working condition, the rod chamber of the asymmetric hydraulic cylinder 3 is the high-pressure chamber, and the rodless chamber is the low-pressure chamber. The electric energy storage unit 6 supplies power to the first servo motor 2 and the bidirectional hydraulic pump 1 to make the bidirectional hydraulic pump 1 rotate reversely. The oil flows from the rodless chamber through the hydraulic motor 4 into the rod chamber to make the piston rod retract. When the oil flows through the hydraulic motor 4, the hydraulic motor 4 is driven by the oil to rotate and drive the generator 5, so as to convert the hydraulic energy into electric energy and store it in the electric energy storage unit 6 for subsequent use. The excess oil can flow from the second overflow valve 12 into the accumulator 10 to compensate for the asymmetric flow.

[0035] When the piston rod of the asymmetric hydraulic cylinder 3 retracts downward and the load force is downward, that is, in the over-retraction condition of the fourth quadrant movement in the four-quadrant working condition, the rodless chamber of the asymmetric hydraulic cylinder 3 is the high-pressure chamber, and the rod chamber is the low-pressure chamber. At this time, the electric energy storage unit 6 can stop supplying power to the bidirectional hydraulic pump 1 to achieve energy-saving. The oil can flow from the rodless chamber through the hydraulic motor 4 and the bidirectional hydraulic pump 1 into the rod chamber under the action of the load force and its own weight to make the piston rod retract. The hydraulic motor 4 will also be driven by the high-pressure oil at this time to drive the generator 5 to rotate and store the hydraulic energy in the form of electric energy in the electric energy storage unit 6; similarly to the third quadrant, the high-pressure chamber circuit composed of the first oil port of the bidirectional hydraulic pump 1 and the rodless chamber of the asymmetric hydraulic cylinder 3 will open the second overflow valve 12, so that the excess flow enters the accumulator 10 for storage to compensate for the asymmetric flow. Of course, the oil can also flow from the first overflow valve 11 into the accumulator 10 for storage.

[0036] To further analyze the working principle, it is described by the mathematical equations in the working process. The force balance equation of the boom hydraulic cylinder is

[0037]

[0038] In the formula: F is the load borne by the boom hydraulic cylinder; p1 and p2 are the pressures of the rodless chamber and the rod chamber of the boom hydraulic cylinder respectively; A1 and A2 are the piston acting areas of the rodless chamber and the rod chamber of the boom cylinder respectively; F fis the piston friction force; m is the sum of the external load mass; x is the displacement of the hydraulic cylinder piston; b m is the viscous damping of the piston and the load.

[0039] According to the flow continuity equation, ignoring the leakage and deformation of the hydraulic cylinder, the flow continuity equation of the boom hydraulic cylinder is

[0040] Q1A1 = Q2A2

[0041] where: Q1 and Q2 are the flows into the rodless chamber and the rod chamber of the hydraulic cylinder respectively; V1 and V2 are the oil volumes flowing into the rodless chamber and the rod chamber of the hydraulic cylinder respectively; β e is the effective bulk modulus of elasticity of the hydraulic oil.

[0042] The motor output torque balance equation is:

[0043]

[0044] where: T E is the torque output by the motor; η T is the effective efficiency of the motor output torque.

[0045] The output power of the motor is

[0046]

[0047] where: is P E is the electric power output by the motor; n is the rotational speed of the motor; η E is the mechanical efficiency of the motor.

[0048] Therefore, in this embodiment, by setting the bidirectional servo motor and the bidirectional hydraulic pump 1, it is possible to drive the oil to flow bidirectionally, match the load conditions, achieve seamless switching in the four quadrants, the structure is simpler, and the complexity of the pipelines in the hydraulic system is significantly reduced; moreover, in this embodiment, a hydraulic motor 4 and a generator 5 are arranged in parallel with the first one-way valve 7 on the second oil path, which can collect the energy of the oil discharged from the rodless chamber. At the same time, under the condition of a forward load, the system can suspend the energy supply of the main pump and directly use the kinetic energy of the load to drive the hydraulic motor 4 to generate electricity, further reducing energy consumption.

[0049] Such as Figure 2As shown in the figure, in this embodiment, the second check valve 8 and / or the third check valve 9 is a pilot-operated check valve. The pilot-operated pipeline of the second check valve 8 is connected to the first oil circuit, and the pilot-operated pipeline of the third check valve 9 is connected to the second oil circuit. When the second check valve 8 is an ordinary check valve, it is applicable to the working conditions where the accumulator 10 compensates for little flow. When the second check valve 8 is a pilot-operated check valve and the second oil circuit is a high-pressure oil circuit, the second check valve 8 conducts reversely; in the over-retraction working condition in the above-mentioned fourth quadrant, after the second check valve 8 conducts reversely, the oil can flow into the accumulator 10 from the second check valve 8 with a smaller pressure drop instead of entering the accumulator 10 from the first relief valve 11 and the second relief valve 12. When the third check valve 9 is a pilot-operated check valve and the first oil circuit is a high-pressure oil circuit, the third check valve 9 conducts reversely; in the impedance retraction working condition in the above-mentioned third quadrant, after the third check valve 9 conducts reversely, after the oil drives the generator 5 to generate electricity through the hydraulic motor 4, the excess oil can enter the accumulator 10 from the third check valve 9 without having to overcome the pressure of the second relief valve 12, thereby reducing energy consumption and improving power generation efficiency.

[0050] In this embodiment, a first stop valve 13 parallel to the asymmetric hydraulic cylinder 3 is provided between the first oil circuit and the second oil circuit. The first stop valve 13 can be a two-position two-way directional control valve. The first stop valve 13 is in a closed state during the normal operation of the hydraulic cylinder; in the impedance extension stage of the asymmetric hydraulic cylinder 3, if the power is insufficient to supply the first servo motor 2 and the bidirectional hydraulic pump 1, and it is required that the hydraulic cylinder retracts or in other actual working conditions, it is required that the asymmetric hydraulic cylinder 3 retracts quickly, the first stop valve 13 can be opened to connect the rodless cavity and the rod cavity of the asymmetric hydraulic cylinder 3, so that the oil can flow back quickly. At this time, the system will not generate energy consumption, and the effects of protecting the equipment, saving energy, and enabling the hydraulic cylinder to respond quickly can be achieved.

[0051] This embodiment further includes a second shutoff valve 14 and a proportional flow control valve 15 arranged in parallel, both of which are connected in series with the hydraulic motor 4. The second shutoff valve 14 can also be a two-position two-way reversing valve. When the hydraulic motor 4 recovers energy, the speed sensor 16 monitors the speed of the hydraulic motor 4 and transmits the speed information to the controller 22. The controller 22 dynamically adjusts the opening and closing of the second stop valve 14 and the proportional flow control valve 15 according to the speed and load of the hydraulic motor 4. When the oil flow through the hydraulic motor 4 is low, the speed of the hydraulic motor 4 is also low. When the speed of the hydraulic motor 4 is 0-1000 rpm, the low-speed circuit of the second stop valve 14 is opened. The structure of the second stop valve 14 is simple and convenient, and can allow the oil with a low flow rate to pass directly without controlling the oil flow rate. When the speed is 1000 rpm-3000 rpm, it means that the oil flow through the hydraulic motor 4 is large. In order to ensure that the hydraulic motor 4 can work stably, the high-speed circuit of the proportional flow control valve 15 is opened at this time to control the oil flow through the hydraulic motor 4 to be stable within an appropriate range, ensuring that the hydraulic motor 4 can normally and stably drive the generator 5 to generate electricity, thereby ensuring that energy can be recovered to the maximum extent at low and high speeds. Of course, the speed at which the second shut-off valve 14 and the proportional flow control valve 15 are switched should be determined according to the specifications of the hydraulic motor 4 and other actual conditions. Without the second shut-off valve 14 and the proportional flow control valve 15, this embodiment can be applied to equipment with little energy recovery, replacing multi-stage energy recovery with direct energy recovery and simplifying the system, such as Figure 3 shown.

[0052] This embodiment also includes a one-way hydraulic pump 17, which is transmission-connected to a second servo motor 18. The oil inlet of the one-way hydraulic pump 17 is connected to the oil reservoir, and the oil outlet is connected to the first oil circuit. The second servo motor 18 drives the one-way hydraulic pump 17 to rotate, replenishing oil in the system. In this embodiment, a filter 19 and a fourth one-way valve 20 are sequentially disposed between the oil outlet of the one-way hydraulic pump 17 and the first oil circuit.

[0053] This embodiment further includes a first motor driver 23, a second motor driver 24, and a third motor driver 25 that are communicatively connected to the first servo motor 2, the generator 5, and the second servo motor 18, respectively. The first motor driver 23, the second motor driver 24, and the third motor driver 25 are all communicatively connected to the controller 22 and the electrical energy storage unit 6. This embodiment also includes a lighting device 26 and a cooling fan 27 that are communicatively connected to the electrical energy storage unit 6.

[0054] In this embodiment, the first servo motor 2 , the generator 5 and the second servo motor 18 are all integrated generators and motors, and the first servo motor 2 and the generator 5 have a bidirectional speed-varying function.

[0055] When the electric energy storage unit 6 reuses energy, the electric energy storage unit 6 will preferentially supply energy to the energy recovery circuit composed of the second servo motor 18 and the hydraulic motor 4 and the oil replenishing circuit when the hydraulic system needs to replenish oil. When there is enough energy, the excess electric energy will be supplied to the connected cooling fan 27 and lighting equipment 26 to achieve the maximum benefit of energy recovery and reuse.

[0056] In the hydraulic cylinder hydraulic system of this embodiment, a check valve is used in parallel with the energy recovery circuit. In the energy recovery circuit, a multi-stage energy recovery circuit and an oil replenishing circuit formed by connecting two different valves in parallel and then connecting them in series with the hydraulic motor 4 are adopted. When the piston rod of the asymmetric hydraulic cylinder 3 extends, it is the same as the ordinary closed-loop pump control system. When the piston rod retracts, all the oil in the rodless chamber of the hydraulic cylinder passes through the multi-stage energy recovery of the hydraulic motor 4 to achieve the maximum energy recovery. The hydraulic energy of the oil is stored in the electric energy storage unit 6 in the form of electric energy, and this part of the stored energy acts on the first servo motor 2 and the bidirectional hydraulic pump 1 in the next cycle to achieve the effects of energy recovery and high energy efficiency, as well as the energy consumption during oil replenishment in the oil replenishing circuit. When there is enough energy, the excess energy can be used for external equipment to achieve the maximum benefit of energy recovery and reuse. At the same time, by using a two-position two-way valve in parallel with the asymmetric hydraulic cylinder 3, the system has a second mode when dealing with the retraction of the hydraulic cylinder, allowing the hydraulic cylinder to directly use the gravitational potential energy of the oil to quickly return the oil, achieving the quick retraction of the hydraulic cylinder and no energy consumption in the system, so as to adapt to different working conditions and avoid energy waste. Not all the electric energy in the circuit is supplied by the electric energy storage unit 6. The electric energy storage unit 6 only plays an auxiliary role, and the main energy source is DC power supply or engine power supply.

[0057] Figure 4 It is the energy transfer chain in this embodiment. Specifically, the DC power supply or the engine and the electric energy storage unit 6 are the energy sources, mainly supplying electric energy to the first servo motor 2 and the second servo motor 18, and also supplying power to the cooling fan 27 and lighting equipment 26 under specific conditions. The first servo motor 2 and the second servo motor 18 convert the electric energy into mechanical energy and respectively transfer it to the bidirectional hydraulic pump 1 and the unidirectional hydraulic pump 17. The bidirectional hydraulic pump 1 and the unidirectional hydraulic pump 17 then convert this part of the mechanical energy into hydraulic energy and transfer it to the asymmetric hydraulic cylinder 3. The asymmetric hydraulic cylinder 3 receives the hydraulic energy of the bidirectional hydraulic pump 1 and the unidirectional hydraulic pump 17 and drives the external load to do work. During the energy recovery process, the hydraulic motor 4 converts the hydraulic energy into mechanical energy and feeds it back to the generator 5 to achieve energy recovery. The accumulator 10 in the hydraulic system is used to store and release hydraulic energy to optimize the energy utilization of the system. At the same time, under specific conditions, the hydraulic energy can be converted into potential energy by opening the first stop valve 13 to achieve potential energy recovery.

[0058] Such as Figure 5 、Figure 6 As shown, this embodiment further includes an intelligent cloud diagnosis collaborative decision-making module. Specifically, through the database 34 and the human-machine hybrid decision-making of the operator, the working state of the loader or other construction machinery is fault diagnosed and corresponding processing is carried out to increase the reliability of the loader. First, it is compared with the database 34 according to the identifier, and then the actual data and the cloud data are compared and analyzed through analysis to analyze whether the actual data is old-type data (data related to the database 34) or new-type data (data not related to the database 34). When it is judged as old-type data, the corresponding operation is performed on the controller 22 according to the operation in the cloud to perform post-fault processing; if it is judged as new-type data, the analyzer sends the new-type data to the operator, and the operator performs manual operation on the controller 22 according to the transmitted data to perform post-fault processing. At the same time, the operator imports the new-type data into the database 34, and the database 34 records the relevant data for subsequent facing the same operation. At the same time, during the entire fault diagnosis process, all data will be sent to the operator. After the operator sets the threshold, the relevant data will prompt the operator after exceeding the threshold to prevent accidents from occurring. At the same time, during the entire process, the database 34 records the fault solution of each operator. The more times it faces, the richer the database 34 in the cloud will be. Multiple machines can share a cloud database 34 to achieve the effect of cluster collaborative optimization.

[0059] The intelligent cloud diagnosis collaborative decision-making module in this embodiment further includes a database 34 and a difference analyzer 35 in addition to the controller 22. This embodiment further includes a first pressure sensor 28 for measuring the pressure of the first oil port, a second pressure sensor 29 for measuring the pressure of the rod chamber, and a third pressure sensor 30 for measuring the pressure of the rodless chamber. The first pressure sensor 28, the second pressure sensor 29, the third pressure sensor 30, and the difference analyzer 35 are all communicatively connected to the database 34. The difference analyzer 35 is communicatively connected to the database 34 and the controller 22. The database 34 is used to store the normal working values under different working conditions and the solutions for abnormal working of the hydraulic control system. The controller 22 is used to control the first servo motor 2, the generator 5, and the second servo motor 18 to act under different abnormal working conditions according to the solutions in the database 34.

[0060] This embodiment further includes a first vibration sensor 31, a second vibration sensor 32, a third vibration sensor 33, and a fourth vibration sensor communicatively connected to the database 34. The first vibration sensor 31, the second vibration sensor 32, the third vibration sensor 33, and the fourth vibration sensor are respectively used to measure the vibration amplitude of the piston rod in the asymmetric hydraulic oil, the vibration amplitude of the hydraulic motor 4, the vibration amplitude of the bidirectional hydraulic pump 1, and the vibration amplitude of the unidirectional hydraulic pump 17.

[0061] In one type of fault, during the operation of a loader or other construction machinery, there may be a situation where the actuators of the hydraulic system, namely the boom and the stick, move slowly. At this time, the pressures at both ends of the asymmetric hydraulic cylinder 3 can be monitored according to the second pressure sensor 29 and the third pressure sensor 30, and compared with the normal working pressure range in the database 34 under the action of the difference analyzer 35 to distinguish between old-class data and new-class data and adjust the controller 22 according to different situations. Here, new-class data is taken as an example for illustration: If the pressure monitored by the pressure sensor is higher after the comparison by the difference analyzer 35, it may be a problem with the displacement of the bidirectional hydraulic pump 1. The operator can adjust the displacement of the bidirectional hydraulic pump 1 by controlling the controller 22 after checking for safety valve and pipeline blockages. At the same time, the controller 22 will feedback the corresponding operation to the database 34 for recording. If the same problem is encountered next time, the displacement of the bidirectional hydraulic pump 1 can be directly adjusted to solve the problem. If the pressure monitored by the pressure sensor is lower after the comparison by the difference analyzer 35, it may be a problem of oil leakage. At this time, the pressure of the first pressure sensor 28 can be observed synchronously. If the pressure at this point is also low, the operator can open the oil replenishment circuit through the controller 22 to replenish the hydraulic system. Similarly, the controller 22 will also feedback the corresponding operation to the database 34 for recording to handle the same situation. When similar faults in the hydraulic system occur frequently, the loader can perform self-adjustment under the monitoring of the operator.

[0062] In another type of fault, during the operation of a loader or other construction machinery, the hydraulic system makes abnormal noises, and there are many situations caused by the noises. Here, the intelligent cloud diagnosis cooperation module is only used to diagnose whether the noise problem is caused by key components. A first vibration sensor 31 is added at the piston rod of the asymmetric hydraulic cylinder 3, a second vibration sensor 32 is added at the hydraulic motor 4, a third vibration sensor 33 is added at the bidirectional hydraulic pump 1, and a fourth vibration sensor is added at the unidirectional hydraulic pump 17 in the oil replenishment circuit. During the normal operation of the hydraulic system, the vibration amplitudes of these key components usually remain within a certain range. These normal data can be recorded in the database 34 first. When abnormal noises occur in the hydraulic system, the difference analyzer 35 compares the signals transmitted by these four vibration sensors with those in the database 34 to determine which specific component makes the abnormal noise. Then, after the operator determines the abnormal vibration, the machine can be stopped to take corresponding measures for the component. At the same time, the controller 22 records the shutdown operation after the abnormal vibration. When abnormal noises occur again next time, the signal of the component with abnormal vibration will be transmitted to the operator and then the machine will be stopped for processing to timely discover potential fault problems and improve the reliability of the loader.

[0063] If the temperature of the hydraulic oil remains above 80°C for a long time, the viscosity of the hydraulic oil will decrease, and the volumetric efficiency of the hydraulic pump will also decrease, resulting in the destruction of the oil film of hydraulic components, an increase in frictional resistance, an increase in wear, and a reduction in the service life of hydraulic components. Therefore, a temperature sensor can also be added to the hydraulic system circuit to monitor the temperature of the hydraulic oil, and cooling measures for the hydraulic oil can be carried out through the controller 22.

[0064] During the entire fault diagnosis process, the operator receives all the data and the data processed by the difference analyzer 35. Therefore, after a system anomaly occurs, the operator can shut down the intelligent cloud diagnosis collaboration module and manually take over the hydraulic system.

[0065] Adaptations made according to actual needs are within the scope of protection of the present invention.

[0066] Specific examples are used in the present invention to illustrate the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A hydraulic control system for an asymmetric hydraulic cylinder, characterized in that, Comprising: A two-way hydraulic pump, which is drivingly connected to a first servo motor. The first oil port and the second oil port of the two-way hydraulic pump are respectively connected to the rod chamber and the rodless chamber of an asymmetric hydraulic cylinder through a first oil circuit and a second oil circuit; a first one-way valve is arranged between the second oil port and the rodless chamber; A hydraulic motor, which is drivingly connected to a generator, and the generator is connected to an electrical energy storage unit; the hydraulic motor is arranged in parallel with the first one-way valve; And an accumulator, which is respectively communicated with the first oil circuit and the second oil circuit through a second one-way valve and a third one-way valve; a first overflow valve and a second overflow valve are respectively arranged between the first oil circuit and the accumulator, and between the second oil circuit and the accumulator. The first overflow valve is arranged in parallel with the second one-way valve, and the second overflow valve is arranged in parallel with the third one-way valve.

2. The hydraulic control system of the asymmetric hydraulic cylinder according to claim 1, characterized in that, The second one-way valve and / or the third one-way valve is a pilot-operated one-way valve. The pilot-operated pipeline of the second one-way valve is communicated with the first oil circuit, and the pilot-operated pipeline of the third one-way valve is communicated with the second oil circuit.

3. The hydraulic control system of the asymmetric hydraulic cylinder according to claim 1, characterized in that, A first stop valve in parallel with the asymmetric hydraulic cylinder is arranged between the first oil circuit and the second oil circuit.

4. The hydraulic control system of the asymmetric hydraulic cylinder according to claim 1, characterized in that, Also included are a second stop valve and a proportional flow control valve arranged in parallel, and both the second stop valve and the proportional flow control valve are connected in series with the hydraulic motor.

5. The hydraulic control system of the asymmetric hydraulic cylinder according to claim 1, characterized in that, Also included is a one-way hydraulic pump drivingly connected to a second servo motor. The oil inlet of the one-way hydraulic pump is communicated with an oil sump, and the oil outlet is communicated with the first oil circuit.

6. The hydraulic control system of the asymmetric hydraulic cylinder according to claim 5, characterized in that, A filter and a fourth one-way valve are sequentially arranged between the oil outlet of the one-way hydraulic pump and the first oil circuit.

7. The hydraulic control system of the asymmetric hydraulic cylinder according to claim 6, characterized in that, Also included are a first motor driver, a second motor driver and a third motor driver respectively communicatively connected to the first servo motor, the generator and the second servo motor. The first motor driver, the second motor driver and the third motor driver are all communicatively connected to the controller and the electrical energy storage unit.

8. The hydraulic control system of the asymmetric hydraulic cylinder according to claim 1, characterized in that, Also included are a lighting device and a cooling fan communicatively connected to the electrical energy storage unit.

9. The hydraulic control system of the asymmetric hydraulic cylinder according to claim 7, characterized in that, Also included are a first pressure sensor for measuring the pressure of the first oil port, a second pressure sensor for measuring the pressure of the rod chamber, a third pressure sensor for measuring the pressure of the rodless chamber, a database and a difference analyzer. The first pressure sensor, the second pressure sensor, the third pressure sensor and the difference analyzer are all communicatively connected to the database. The difference analyzer is communicatively connected to the database and the controller. The database is used for storing the normal working values under different working conditions and the solutions for the abnormal working of the hydraulic control system. The controller is used for controlling the actions of the first servo motor, the generator and the second servo motor under different abnormal working conditions according to the solutions in the database.

10. The hydraulic control system of the asymmetric hydraulic cylinder according to claim 9, characterized in that, It further includes a first vibration sensor, a second vibration sensor, a third vibration sensor, and a fourth vibration sensor that are communicatively connected to the database. The first vibration sensor, the second vibration sensor, the third vibration sensor, and the fourth vibration sensor are respectively used to measure the vibration amplitude of the piston rod in the asymmetric hydraulic cylinder, the vibration amplitude of the hydraulic motor, the vibration amplitude of the bidirectional hydraulic pump, and the vibration amplitude of the unidirectional hydraulic pump.

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