Pump-controlled hydraulic loop structure with energy feedback function and control method

Abstract

The invention discloses a pump-controlled hydraulic loop structure with an energy feedback function and a control method. A two-way hydraulic pump / motor is arranged between two oil ways of a rodless cavity and a rod cavity of a hydraulic execution element; a first hydraulic control one-way valve and a first electromagnetic directional valve are arranged on the rodless cavity oil way, and the first electromagnetic directional valve can be communicated with the first hydraulic control one-way valve. A second hydraulic control one-way valve, a second electromagnetic directional valve and a third low-pressure overflow valve are arranged on the rod cavity oil way, and the second electromagnetic directional valve can be communicated with the third low-pressure overflow valve to release pressure and flow. An oil way is connected between an oil inlet of the first hydraulic control one-way valve and an oil inlet of the second hydraulic control one-way valve and used for opening the rod cavity through hydraulic pressure of the rodless cavity. When the piston rod retreats, gravitational potential energy of a load can be recycled to generate power for the motor, and energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic control, and in particular to a pump control hydraulic circuit structure with energy feedback function and a control method. Background Art

[0002] As energy shortage and environmental pollution become increasingly serious worldwide, energy conservation and emission reduction technology is a hot topic of research. Hydraulic transmission technology has penetrated into almost all modern engineering construction fields and is the most important power transmission method in automatic control and engineering machinery actuators, but its total energy utilization rate is low.

[0003] The existing hydraulic system basically controls the speed of the working device in the form of motor-hydraulic pump / motor-multi-way valve-actuator. The motor drives the hydraulic pump / motor, and the multi-way valve distributes the hydraulic energy to each actuator. Whether it is the control mode of motor+variable pump+load sensitive valve or the control mode of motor+fixed pump+throttle valve, there is a certain amount of energy loss, and a large amount of energy is consumed in the throttle port and the relief valve.

[0004] Moreover, most hydraulic systems currently use centralized hydraulic control systems. The power oil from the hydraulic pump / motor is used to balance the load and distribute the flow of multiple actuators through an integral multi-way valve. The loads of the centralized hydraulic system are coupled with each other, resulting in low system operation efficiency. The hydraulic pipelines of the system with centralized pressure oil supply are long, which will also cause unnecessary pressure loss along the way. It is reported that the efficiency of the hydraulic system of construction machinery is about 30%. A large amount of hydraulic energy loss is converted into heat energy, causing the system to heat up, and the system efficiency is low.

[0005] In addition, it is found in actual engineering that when the load carried by the hydraulic actuator has gravitational potential energy, this part of the energy occupies a large proportion of the entire working condition, and the energy generated by gravitational work is all used for system heating. If this part of the energy can be utilized by the hydraulic system, it will save about 50% of the energy consumption in the lifting condition. Summary of the invention

[0006] In order to reduce unnecessary energy loss of the hydraulic system and give full play to the power advantage of the hydraulic system, the present invention proposes a pump-controlled hydraulic circuit structure and control method with energy feedback function based on the characteristics of the three-electric technology. Its main features are that a hydraulic working device is a separate hydraulic system, which is composed of a separate motor, a hydraulic pump / motor, a working device and related auxiliary hydraulic components that are integrated together. The motor adopts speed control to adjust the flow of the hydraulic system at different speeds according to the output of the operator; the hydraulic pressure required by the system is provided by the adaptive motor torque, and energy recovery is achieved by the motor power generation when the gravitational potential energy is doing work; the hydraulic pump / motor converts torque into hydraulic energy; the working device is responsible for providing power to the outside world; and the related auxiliary hydraulic components protect the realization of the system function.

[0007] The technical solution of the present invention is:

[0008] A pump-controlled hydraulic circuit structure with energy feedback function, provided with an oil tank, a filter, a system overflow valve, a motor and a bidirectional hydraulic pump / motor;

[0009] The oil tank is a bidirectional hydraulic pump / motor that supplies oil in both directions;

[0010] The two ends of the bidirectional hydraulic pump / motor are respectively connected to two oil circuits, leading to the rodless chamber and rod chamber of the hydraulic actuator, or the oil inlet and outlet of the drive motor;

[0011] On the oil circuit leading to the rodless chamber of the hydraulic actuator, a hydraulically controlled one-way valve and an electromagnetic reversing valve are arranged, one end of the electromagnetic reversing valve is connected to the oil circuit between the oil outlet of the rodless chamber of the hydraulic actuator and the oil outlet of the hydraulically controlled one-way valve, and the other end is connected to the control end of the hydraulically controlled one-way valve;

[0012] On the oil circuit leading to the rod chamber of the hydraulic actuator, a hydraulically controlled one-way valve 2, an electromagnetic reversing valve 2 and a low-pressure relief valve 3 are arranged. One end of the electromagnetic reversing valve 2 is connected to the oil circuit at the front end of the oil inlet of the hydraulically controlled one-way valve 2, and the other end is connected to the oil inlet of the low-pressure relief valve 3. The oil outlet of the low-pressure relief valve 3 is connected to the oil tank.

[0013] An oil circuit is also connected between the oil circuit at the oil inlet front end of the hydraulically controlled one-way valve 1 and the control end of the hydraulically controlled one-way valve 2.

[0014] Furthermore, the hydraulically controlled one-way valve 1 and the hydraulically controlled one-way valve 2 are both normally closed hydraulically controlled one-way valves; the electromagnetic reversing valve 1 and the electromagnetic reversing valve 2 are both normally closed electromagnetic reversing valves.

[0015] Furthermore, ordinary one-way valves are respectively provided on the two oil supply pipelines connecting the oil tank to the bidirectional hydraulic pump / motor; and system overflow valves are respectively provided on the two oil lines connecting the bidirectional hydraulic pump / motor to the hydraulic actuator.

[0016] Furthermore, the overflow pressure of the low-pressure overflow valve is lower than the system pressure.

[0017] A control method for the pump control hydraulic circuit structure with energy feedback function as described above, characterized in that:

[0018] The handle opening corresponding to the motor speed and the action speed of the hydraulic actuator are calibrated in advance, and the motor torque is adaptive;

[0019] (1) When the handle operation command requires the piston rod of the hydraulic actuator to retract, the motor speed is controlled according to the handle opening, and the motor drives the bidirectional hydraulic pump / motor to supply oil from the rodless chamber to the rod chamber;

[0020] At the same time, the electromagnetic reversing valve 1 is powered on to make the electromagnetic reversing valve 1 conductive, and the oil in the rodless chamber passes through the electromagnetic reversing valve 1 to open the hydraulic control check valve 1;

[0021] Then the oil in the rodless chamber flows to the bidirectional hydraulic pump / motor through the hydraulic control check valve 1, and after flowing out of the bidirectional hydraulic pump / motor, the hydraulic control check valve 2 is opened, and the hydraulic oil enters the rod chamber;

[0022] At the same time, the electromagnetic reversing valve 2 is powered on to make the electromagnetic reversing valve 2 conductive, and the oil flowing out of the bidirectional hydraulic pump / motor overflows through the hydraulic control check valve 2 and the low-pressure relief valve 3;

[0023] During this process, the bidirectional hydraulic pump / motor provides reverse torque to the motor for generating electricity;

[0024] (2) When the handle operation command requires the piston rod of the hydraulic actuator to extend, the motor speed is controlled according to the handle opening, and the motor drives the bidirectional hydraulic pump / motor to supply oil from the rod chamber to the rodless chamber;

[0025] This process does not require powering on the electromagnetic reversing valve 1 and the electromagnetic reversing valve 2;

[0026] Initially, oil is pumped from the oil tank under the driving action of the bidirectional hydraulic pump / motor. After the oil passes through the bidirectional hydraulic pump / motor, the hydraulic control check valve is opened, and the oil enters the rodless chamber of the hydraulic actuator, pushing the piston to move toward the rod chamber.

[0027] At the same time, the hydraulic oil in an oil circuit leading from the front end of hydraulically controlled one-way valve one to the control end of hydraulically controlled one-way valve two opens the hydraulically controlled one-way valve two, the oil circuit of the rod chamber is opened, the oil flows out of the rod chamber, and circulates through the two-way hydraulic pump / motor to the rodless chamber.

[0028] The technical advantages of the present invention are: eliminating the valve shoulder pressure loss caused by the hydraulic system multi-way valve not being fully opened; eliminating the pressure loss caused by the pressure compensation of the valve when multiple working devices are working at the same time; eliminating the energy waste caused by the mid-position oil return; reducing the pressure loss along the pipeline; most of the energy loss caused by overflow is avoided; and realizing partial energy recovery and utilization of the hydraulic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Structural principle diagram of a pump-controlled hydraulic circuit with energy feedback function provided by the present invention. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with the embodiments. Those skilled in the art should know that the following embodiments are not the only limitations on the technical solutions of the present invention, and any equivalent changes or modifications made within the spirit of the technical solutions of the present invention should be deemed to fall within the protection scope of the present invention.

[0031] As shown in Figure 1, the pump control hydraulic circuit structure with energy feedback function of the present invention adopts a pump control drive scheme in which a working device is an independent hydraulic unit composed of a set of motors, hydraulic pumps / motors, actuators and working valve groups. In this type of scheme, a set of motors, hydraulic pumps / motors and valve groups only controls the working state of one working device, so the independent controllability is strong; on the other hand, the selection of motors, pumps and valves only needs to be configured according to the working requirements of the controlled device, without considering the requirements of other working devices, so the selection backup power will also be reduced a lot; on the other hand, the independent drive hydraulic system can be arranged close to the working device, saving the length of the oil circuit and the loss along the oil circuit. These are the advantages of pump control drive, and the structure of the present invention is suitable for pump control drive system.

[0032] The hydraulic circuit is controlled by the motor, hydraulic pump / motor and valve group to control the flow state of the hydraulic oil in the circuit. The so-called flow state includes: 1) the hydraulic oil flows into one hydraulic cavity of the hydraulic actuator and flows out from the other hydraulic cavity (thereby realizing the operation and switching adjustment of the working device); 2) the hydraulic oil stops flowing between the two hydraulic cavities (that is, the working state stops); 3) the flow rate of the hydraulic oil in the circuit is adjusted; 4) the pressure of the hydraulic oil in the circuit is adjusted. The present invention also controls these flow states.

[0033] In the hydraulic circuit structure of the present invention, a motor 1, a bidirectional hydraulic pump / motor 2, a common check valve 1 3, a common check valve 2 4, a hydraulic control check valve 1 5, a hydraulic control check valve 2 6, an electromagnetic reversing valve 1 7, an electromagnetic reversing valve 2 8, a system overflow valve 1 9, a system overflow valve 2 10, a low-pressure overflow valve 3 11 and a hydraulic actuator 12 are mainly provided. The oil tank 13 and the filter 14 and other auxiliary components are essential facilities of the hydraulic system. The hydraulic actuator 12 forms a hydraulic circuit through these components. The hydraulic actuator 12 can convert hydraulic energy into mechanical energy (including gravitational heat energy and kinetic energy) to drive the working device to work; it can also convert mechanical energy into hydraulic energy to drive the motor 1 to generate electricity. In the present invention, a double-acting hydraulic actuator is used, including two hydraulic chambers, one is a rodless chamber, and the other is a rod chamber (or a pump / motor with a driving effect). That is, the hydraulic actuator 12 in this article can refer to a hydraulic cylinder or a hydraulic pump / motor.

[0034] exist Figure 1 In the circuit structure shown, the oil in the oil tank 13 is filtered by the filter 14 and then supplied to the outside. The oil supply pipeline of the oil tank is divided into two routes, which are respectively connected to the two ends of the two-way hydraulic pump / motor 2, and are used to provide two-way oil supply for the two-way hydraulic pump / motor 2. A common check valve 1 3 and a common check valve 2 4 are respectively arranged at the two ends of the oil supply of the oil tank. The common check valve 1 3 and the common check valve 2 4 have the function of common one-way conduction to prevent backflow. Under the driving action of the hydraulic pump / motor, the one-way valve on one side opens to supply oil to the outside.

[0035] In order to realize the formation of a circulating circuit between the two chambers of the hydraulic actuator 12, the present invention adopts a reversing drive of a bidirectional hydraulic pump / motor 2, and an oil circuit A leading to the rodless chamber of the hydraulic actuator 12 and an oil circuit B leading to the rod chamber of the hydraulic actuator 12 are respectively arranged at both ends of the bidirectional hydraulic pump / motor 2. The oil circuit A and the oil circuit B form a circuit through the bidirectional hydraulic pump / motor 2. The bidirectional hydraulic pump / motor 2 has a bidirectional driving function, which can realize the flow of hydraulic oil from the rodless chamber of the hydraulic actuator 12 to the rod chamber, and from the rod chamber to the rodless chamber. This structure can make the hydraulic oil flow alternately or be stationary between the two chambers, avoiding the frequent entry and exit of the single-chamber oil circuit in the oil tank and avoiding energy loss. The bidirectional hydraulic pump / motor 2 is driven by the motor 1, and the speed control of the motor 1 is pre-calibrated by the action speed requirement of the working device corresponding to the handle opening.

[0036] The present invention is provided with a system overflow valve 1 9 on the oil circuit A, and a system overflow valve 2 10 on the oil circuit B. The system overflow valve 1 9 and the system overflow valve 2 10 are both connected back to the oil tank. The overflow pressures of the system overflow valve 1 9 and the system overflow valve 2 10 are both set to the system pressure. When the oil supply pressures of the oil circuit A and the oil circuit B exceed the system pressure, the system releases pressure through the respective system overflow valves.

[0037] In addition, the present invention further provides a hydraulically controlled one-way valve 5 on the oil circuit A and a hydraulically controlled one-way valve 6 on the oil circuit B. Both hydraulically controlled one-way valves are normally closed hydraulically controlled one-way valves, which can only be opened by relying on the oil circuit pressure. When the system is not working, the hydraulically controlled one-way valve is closed to ensure the hydraulic stability of the two chambers of the working device. The hydraulically controlled one-way valve is opened only when the pressure between the hydraulically controlled one-way valve and the pump is greater than the pressure between the hydraulically controlled one-way valve and the hydraulic actuator, or when the pressure at the control end of the hydraulically controlled one-way valve reaches the starting pressure.

[0038] In particular, the present invention also provides an electromagnetic reversing valve 7 on the oil circuit leading to the rodless chamber of the hydraulic actuator 12, that is, on the oil circuit A. One end of the electromagnetic reversing valve 7 is connected to the hydraulic control check valve 5 and the oil supply pipeline of the hydraulic actuator 12, and the other end is connected to the control port of the hydraulic control check valve 5. The electromagnetic reversing valve 7 is a normally closed electromagnetic reversing valve. The function of the electromagnetic reversing valve 7 is to achieve action coordination in the process of hydraulic energy feedback. The present invention realizes the feedback of hydraulic energy for motor power generation precisely because of the combined structure of the electromagnetic reversing valve 7 and the hydraulically controlled non-return valve 5. Its working principle is: when the pressure on the rodless cavity of the hydraulic actuator 12 is relatively large due to the load gravity (or inertia), if the electromagnetic reversing valve 7 is powered on at this time, the electromagnetic reversing valve 7 is in a conducting state, and the pressure of the hydraulic oil in the rodless cavity of the hydraulic actuator 12 is transmitted to the control port of the hydraulically controlled non-return valve 5 through the electromagnetic reversing valve 7, then the valve port of the hydraulically controlled non-return valve 5 is opened. Once the hydraulically controlled non-return valve 5 is opened, the rodless cavity is connected to the oil circuit A, and the oil in the rodless cavity can flow through the hydraulically controlled non-return valve 5 and flow in the opposite direction along the oil circuit A to the two-way hydraulic pump / motor 2 (the ordinary non-return valve 3 is cut off so it cannot flow back to the oil tank). At this time, the two-way hydraulic pump / motor 2 rotates under the action of the hydraulic pressure, converts the hydraulic energy into mechanical energy, and then delivers the hydraulic oil to the rod cavity of the hydraulic actuator 12 through the hydraulically controlled non-return valve 6. During this process, hydraulic energy is converted into mechanical energy of the bidirectional hydraulic pump / motor 2 for its rotation; at the same time, the bidirectional hydraulic pump / motor 2 is connected to the motor 1, and the rotation speed of the bidirectional hydraulic pump / motor 2 is controlled by the motor 1, that is, the action speed of the actuator is controlled by the motor's reverse drag. Therefore, at this time, the bidirectional hydraulic pump / motor 2 is used as a hydraulic motor to provide mechanical energy to the motor for power generation. The mechanical energy is converted into electrical energy, and the motor acts as an engine.

[0039] This structure is built on the rodless chamber oil circuit of the hydraulic actuator 12. The energy feedback working condition that can be used can be the moment when the piston rod retracts due to the gravity of the load after the hydraulic actuator 12 drives the working device to carry the load; it can also be the moment when the actuator 12 is a motor and the inertia of the driven element drives the motor to rotate.

[0040] In particular, the present invention sets an electromagnetic reversing valve 28 and a low-pressure relief valve 311 on the oil circuit (oil circuit B) leading to the rod chamber of the hydraulic actuator 12. The electromagnetic reversing valve 28 is also a normally closed electromagnetic reversing valve. One end of the electromagnetic reversing valve 28 is connected to the oil circuit B, and the other end is connected to the low-pressure relief valve 311, and the low-pressure relief valve 311 is connected back to the oil tank. The function of this structure is also to achieve the coordinated action in the energy recovery process. When the hydraulic oil in the rodless chamber of the hydraulic actuator 12 is transported to the rod chamber via the two-way hydraulic pump / motor 2, on the one hand, the amount of oil required on the side of the rod chamber is less than the amount of oil discharged from the rodless chamber, so part of the hydraulic oil must return to the oil tank; on the other hand, the pressure on the side of the rod chamber cannot be higher than that of the rodless chamber, otherwise the system cannot work, so a smaller overflow pressure must be set for pressure relief, and the overflow pressure cannot overflow when it reaches the preset system pressure, otherwise the system cannot work without external power. Therefore, an electromagnetic reversing valve 28 and a low-pressure relief valve 3 11 are arranged in the rod chamber oil circuit. When the electromagnetic reversing valve 28 is powered on, the valve port is opened, and the low-pressure relief valve 3 11 sets an overflow pressure which is smaller than the system pressure. Here, 0.01 times of the system pressure can be preferably selected. When the oil circuit pressure reaches the overflow pressure, the excess hydraulic oil returns to the oil tank through the low-pressure relief valve 3 11.

[0041] Furthermore, an oil circuit C is connected between the oil circuit at the oil inlet front end of the hydraulic control check valve 15 and the control end of the hydraulic control check valve 26, and this oil circuit can divert the pressure oil from the pump outlet to the hydraulic control check valve 15 section to the control end of the hydraulic control check valve 26. The function is that when the piston rod of the hydraulic actuator 12 extends outward, the oil is delivered to the rodless chamber through the two-way hydraulic pump / motor 2. When the ordinary check valve 24 is opened and the hydraulic control check valve 15 is also opened, the pressure oil of the rodless chamber oil circuit also opens the hydraulic control check valve 26 through this oil circuit, so that the rod chamber oil circuit is also conducted, and then the oil in the rod chamber is leaked out and supplied to the rodless chamber, realizing the circulation from the rod chamber to the rodless chamber. After that, the oil in the oil tank is only used for replenishing oil.

[0042] Through the above introduction, it can be known that the present invention provides a pump control hydraulic circuit structure with energy feedback function, and the outstanding feature of the structure is: an electromagnetic reversing valve is set on the rodless chamber oil circuit of the hydraulic actuator 12, and the electromagnetic reversing valve has the function of controlling the conduction of the hydraulic control check valve on the oil circuit. When the rodless chamber of the hydraulic actuator 12 is subjected to a large pressure and the piston moves toward the rodless chamber according to the control needs of the operator, and the hydraulic control check valve cannot be actively opened at this time, it can only be opened by the electromagnetic reversing valve to make the rodless chamber oil circuit conductive, and under the action of the hydraulic pump / motor driven by the motor, the oil is replenished to the rod chamber. Since the speed of the pump needs to be controlled by the motor so that the piston rod speed of the hydraulic actuator 12 cannot be out of control, under the current motor speed control, the hydraulic energy will react to the motor through the hydraulic pump / motor to generate electricity, and the hydraulic energy will be converted into electrical energy. At this time, the hydraulic pump / motor is used as a hydraulic motor, and the motor is used as an engine. Therefore, the typical application of this structure is the feedback of the gravitational potential energy of the load, the gravitational potential energy is converted into hydraulic energy, the hydraulic energy is converted into mechanical energy, and the mechanical energy is converted into electrical energy.

[0043] If the hydraulic actuator 12 is a hydraulic motor, the rodless cavity is the flow output end from which energy can be recovered, and the rod cavity is the flow input end from which energy can be recovered.

[0044] The present invention further applies the above structure to provide a control method, the process of which is:

[0045] The handle opening corresponding to the motor speed and the action speed of the hydraulic actuator are calibrated in advance, and the motor torque is adaptive.

[0046] (1) When the handle operation command requires the piston rod of the hydraulic actuator 12 to retract (when the hydraulic oil needs to flow from the rodless chamber to the rod chamber of the hydraulic actuator 12), the motor speed is equal to the speed corresponding to the handle opening, and the motor 1 drives the bidirectional hydraulic pump / motor 2 to rotate and controls the oil supply direction of the bidirectional hydraulic pump / motor 2 from the rodless chamber to the rod chamber;

[0047] At the same time, the electromagnetic reversing valve 7 is energized, so that the electromagnetic reversing valve 7 opens the hydraulic control check valve 5, and the hydraulic oil in the rodless chamber flows through the hydraulic control check valve 5 to the two-way hydraulic pump / motor 2. Since the ordinary check valve 3 is reversely cut off, after the hydraulic oil flows through the two-way hydraulic pump / motor 2, the hydraulic control check valve 26 is opened due to the positive hydraulic pressure, and the hydraulic oil enters the rod chamber;

[0048] At the same time, the electromagnetic reversing valve 2 8 is powered on, so that the electromagnetic reversing valve 2 8 opens the low-pressure relief valve 3 11, and the oil flowing out of the rodless chamber passes through the two-way hydraulic pump / motor 2, and partially overflows on the oil path leading to the rod chamber to relieve pressure;

[0049] During this process, the motor 1 controls the bidirectional hydraulic pump / motor 2 to rotate at a certain speed, and the torque of the bidirectional hydraulic pump / motor 2 drives the motor to generate electricity, thereby realizing energy feedback.

[0050] (2) When the handle operation command requires the piston rod of the hydraulic actuator 12 to extend (when the hydraulic oil needs to flow from the rod chamber of the hydraulic actuator 12 to the rodless chamber), the motor speed is equal to the speed corresponding to the handle opening, and the motor 1 drives the bidirectional hydraulic pump / motor 2 to rotate and controls the oil supply direction of the bidirectional hydraulic pump / motor 2 from the rod chamber to the rodless chamber;

[0051] This process does not require powering on the electromagnetic reversing valve 1 7 and the electromagnetic reversing valve 2 8;

[0052] At this time, negative pressure is formed under the driving action of the two-way hydraulic pump / motor 2, and the ordinary one-way valve 2 4 is opened. First, oil is pumped from the oil tank. After the oil passes through the two-way hydraulic pump / motor 2, the hydraulic control one-way valve 1 5 is opened under the positive hydraulic action, and the hydraulic oil enters the rodless chamber of the hydraulic actuator 12, pushing the piston to move toward the rod chamber.

[0053] At the same time, since the hydraulic oil flows in a negative direction, the oil circuit pressure of the rodless chamber drives the control end of the hydraulically controlled one-way valve 26. Therefore, when the hydraulically controlled one-way valve 26 is opened, the oil circuit of the rod chamber is conducted, and the piston pushes the hydraulic oil out of the rod chamber. Since the two-way hydraulic pump / motor 2 generates negative pressure on its right side, the ordinary one-way valve 24 is reversely cut off, and the oil can only be circulated through the two-way hydraulic pump / motor 2 to supply the rodless chamber. After that, the oil in the oil tank is only used for replenishment.

[0054] During this process, motor 1 drives the bidirectional hydraulic pump / motor 2 throughout the entire process to provide hydraulic oil to the rodless chamber to do work, so there is no energy feedback.

[0055] The above two action processes can be better understood in combination with actual working conditions. For example, when shoveling or lifting heavy objects, the piston rod needs to extend to do work, so it can only consume energy; and when the heavy object lifted by the vertical piston rod falls, the potential energy of the heavy object decreases, and gravity does work. This part of energy not only does not need to be provided by the outside world, but is also recoverable energy.

[0056] The above description is only a specific embodiment of the present application, so that those skilled in the art can understand or implement the present application. However, various equivalent modifications and changes to these embodiments will be obvious to those skilled in the art, and the present application will not be limited to these embodiments without departing from the spirit or scope of the present application, but will comply with the scope consistent with the claims of the present application.

Claims

1. A pump-controlled hydraulic circuit structure with energy feedback function, provided with an oil tank, a filter, a system overflow valve, a motor and a bidirectional hydraulic pump / motor, characterized in that: The oil tank is a bidirectional hydraulic pump / motor that supplies oil in both directions; The two ends of the bidirectional hydraulic pump / motor are respectively connected to two oil circuits, leading to the rodless chamber and rod chamber of the hydraulic actuator, or the oil inlet and outlet of the drive motor; On the oil circuit leading to the rodless chamber of the hydraulic actuator, a hydraulically controlled one-way valve and an electromagnetic reversing valve are arranged, one end of the electromagnetic reversing valve is connected to the oil circuit between the oil outlet of the rodless chamber of the hydraulic actuator and the oil outlet of the hydraulically controlled one-way valve, and the other end is connected to the control end of the hydraulically controlled one-way valve; On the oil circuit leading to the rod chamber of the hydraulic actuator, a hydraulically controlled one-way valve 2, an electromagnetic reversing valve 2 and a low-pressure relief valve 3 are arranged. One end of the electromagnetic reversing valve 2 is connected to the oil circuit at the front end of the oil inlet of the hydraulically controlled one-way valve 2, and the other end is connected to the oil inlet of the low-pressure relief valve 3. The oil outlet of the low-pressure relief valve 3 is connected to the oil tank. An oil circuit is also connected between the oil circuit at the oil inlet front end of the hydraulically controlled one-way valve 1 and the control end of the hydraulically controlled one-way valve 2.

2. The pump-controlled hydraulic circuit structure with energy feedback function according to claim 1 is characterized in that: The hydraulically controlled one-way valve 1 and the hydraulically controlled one-way valve 2 are both normally closed hydraulically controlled one-way valves; The electromagnetic reversing valve 1 and the electromagnetic reversing valve 2 are both normally closed electromagnetic reversing valves.

3. The pump-controlled hydraulic circuit structure with energy feedback function according to claim 1 is characterized in that: On the two oil supply pipelines connecting the oil tank to the bidirectional hydraulic pump / motor, ordinary one-way valves are respectively provided; System overflow valves are respectively provided on the two oil circuits connecting the bidirectional hydraulic pump / motor to the hydraulic actuator.

4. The pump-controlled hydraulic circuit structure with energy feedback function according to claim 1, characterized in that: The overflow pressure of the low-pressure overflow valve is lower than the system pressure.

5. A control method for a pump-controlled hydraulic circuit structure with energy feedback function according to any one of claims 1 to 4, characterized in that: The handle opening corresponding to the motor speed and the action speed of the hydraulic actuator are calibrated in advance, and the motor torque is adaptive; (1) When the handle operation command requires the piston rod of the hydraulic actuator to retract, the motor speed is controlled according to the handle opening, and the motor drives the bidirectional hydraulic pump / motor to supply oil from the rodless chamber to the rod chamber; At the same time, the electromagnetic reversing valve 1 is powered on to make the electromagnetic reversing valve 1 conductive, and the oil in the rodless chamber passes through the electromagnetic reversing valve 1 to open the hydraulic control check valve 1; Then the oil in the rodless chamber flows to the bidirectional hydraulic pump / motor through the hydraulic control check valve 1, and after flowing out of the bidirectional hydraulic pump / motor, the hydraulic control check valve 2 is opened, and the hydraulic oil enters the rod chamber; At the same time, the electromagnetic reversing valve 2 is powered on to make the electromagnetic reversing valve 2 conductive, and the oil flowing out of the bidirectional hydraulic pump / motor overflows through the hydraulic control check valve 2 and the low-pressure relief valve 3; During this process, the bidirectional hydraulic pump / motor provides reverse torque to the motor for power generation; (2) When the handle operation command requires the piston rod of the hydraulic actuator to extend, the motor speed is controlled according to the handle opening, and the motor drives the bidirectional hydraulic pump / motor to supply oil from the rod chamber to the rodless chamber; This process does not require powering on the electromagnetic reversing valve 1 and the electromagnetic reversing valve 2; Initially, oil is pumped from the oil tank under the driving action of the bidirectional hydraulic pump / motor. After the oil passes through the bidirectional hydraulic pump / motor, the hydraulic control check valve is opened, and the oil enters the rodless chamber of the hydraulic actuator, pushing the piston to move toward the rod chamber. At the same time, the hydraulic oil in an oil circuit leading from the front end of hydraulically controlled one-way valve one to the control end of hydraulically controlled one-way valve two opens the hydraulically controlled one-way valve two, the oil circuit of the rod chamber is opened, the oil flows out of the rod chamber, and circulates through the two-way hydraulic pump / motor to the rodless chamber.

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