CN116181709A - A New Closed Pump Control Asymmetric Cylinder System for Electric Construction Machinery - Google Patents

Abstract

The invention provides a new type of closed pump-controlled asymmetrical cylinder system, which can recover the energy of the system under the load condition and generate electricity for the electric energy storage unit through the bidirectional hydraulic pump motor and the bidirectional variable speed servo motor for energy storage. Under the reverse load condition, the electric energy storage unit supplies power to the bidirectional variable speed servo motor and the bidirectional hydraulic pump motor for energy utilization. At the same time, the asymmetric hydraulic cylinder of the system has a third hydraulic chamber directly connected to a small closed pump control system, which can recover and utilize energy through independent control, and can independently drive the small closed pump control system to actively control the flow according to the working conditions And pressure-assisted control of asymmetric hydraulic cylinder actuators to improve system performance. Through the invention, the energy utilization efficiency of the boom of the electric engineering machinery is improved, the energy wasted in the working process is recovered and utilized, and the load capacity and working performance of the boom are improved at the same time.

Description

A New Closed Pump Control Asymmetric Cylinder System for Electric Construction Machinery

technical field

The invention relates to the technical field of closed pump control systems, in particular to a novel closed pump control asymmetric cylinder system for electric engineering machinery.

Background technique

With the development of the national economy and the needs of national construction, engineering project construction plays a pivotal role in the development of the national economy. Excavators are an indispensable type of construction machinery in the rapid development of society. Traditional construction machinery widely adopts the drive system of engine-variable pump-multi-way valve-actuator, which has problems such as high energy consumption, high noise, low operation accuracy and serious oil pollution, etc. The demand for excavators continues to rise and other issues require more and more technical specifications for excavators. Therefore, the development of excavator industrial technology towards green, environmental protection, intelligence, and IoT is an unchanging trend. However, the existing multi-way valve control will inevitably produce throttling loss and overflow loss, and is insufficient in heavy load capacity and energy transfer efficiency, which is easy to cause energy loss. It also affects the use of large noise and low operating accuracy. user experience.

Contents of the invention

The invention discloses a new type of closed pump-controlled asymmetric cylinder system for electric construction machinery, which has simple structure and convenient operation, and aims to improve the problems of high energy consumption, high noise, low operation precision and serious oil pollution in existing construction machinery. question.

The present invention adopts the following scheme: a new type of closed pump-controlled asymmetric cylinder system for electric engineering machinery, including an electric energy storage unit, a fuel tank, and also includes: a first two-way variable speed servo motor, a first two-way hydraulic pump motor, an A symmetrical hydraulic cylinder, a second bidirectional hydraulic pump motor, a second bidirectional variable speed servo motor, a first motor driver, a second motor driver and a controller; wherein, the asymmetric hydraulic cylinder is suitable for connecting to an external load of the system, which includes First chamber, second chamber and third chamber;

The first two-way hydraulic pump motor includes a first oil port and a second oil port, and the first oil port communicates with the first cavity of the asymmetric hydraulic cylinder to form a first cavity oil circuit, and the second oil port communicates with the asymmetric hydraulic cylinder. The second chamber of the hydraulic cylinder is connected to form a second chamber oil passage, the third chamber of the asymmetric hydraulic cylinder is connected to the second bidirectional hydraulic pump motor to form a third chamber oil passage, and the second bidirectional hydraulic pump motor connected to the second bidirectional variable speed servo motor, the second bidirectional variable speed servo motor is electrically connected to the second motor driver; the first bidirectional variable speed servo motor is configured to control the first bidirectional The flow and pressure of the hydraulic pump motor control the actuating direction and actuating speed of the asymmetric hydraulic cylinder;

The electrical energy storage unit is simultaneously connected to the first bidirectional variable speed servo motor and the second bidirectional variable speed servo motor, and is configured such that when the external load of the system is in a parallel load condition, the first bidirectional variable speed servo motor, The second bidirectional variable speed servo motor, the first bidirectional hydraulic pump motor, and the second bidirectional hydraulic pump motor can rotate under the action of an external load to generate electricity to the electric energy storage unit for energy recovery and storage; when the external load of the system is in reverse Under load conditions, the electric energy storage unit can supply power to the controller and the motor driver to drive the first bidirectional variable speed servo motor and the second bidirectional variable speed servo motor to rotate; at this time, the controller and the The second motor driver is configured to drive the second two-way variable-speed servo motor to drive the second two-way hydraulic pump motor to rotate according to the working conditions of the external load of the system to give the pressure in the third chamber of the asymmetric cylinder to achieve asymmetrical cylinder. Large load output of symmetrical hydraulic cylinder.

Further, the asymmetric hydraulic cylinder also includes a magnetostrictive displacement sensor and an extension rod, the extension rod is movably connected to the first chamber and the third chamber, and is suitable for being connected with an electric construction machine to receive An external load of the system; the magnetostrictive displacement sensor is connected to the controller and the extension rod, and is configured to collect displacement data of the extension rod and transmit the data to the controller.

Further, a first one-way valve and a second one-way valve connected to the oil tank are arranged in parallel on the first chamber oil circuit and the second chamber oil circuit of the first two-way hydraulic pump motor, and on the first A first relief valve and a second relief valve connected to the oil tank are arranged in parallel on the one-way valve and the second one-way valve respectively.

Further, the first two-way hydraulic pump motor is also provided with a first two-position two-way solenoid valve in parallel, and the first two-position two-way solenoid valve is arranged between the oil circuit in the first cavity of the asymmetric hydraulic cylinder and the first two-way solenoid valve. Between the oil passages of the second cavity and in the normally closed position.

Further, a second two-position two-way solenoid valve is provided on the oil circuit of the first chamber and is in a normally open position, and a third two-position two-way solenoid valve is provided on the oil circuit of the second chamber and is in a normally open position, The fourth two-position two-way solenoid valve is set on the oil circuit of the third chamber and is in the normally open position; the second two-position two-way solenoid valve, the third two-position two-way solenoid valve, and the fourth two-position two-way solenoid valve The valve is configured to be able to switch on and off of the first chamber oil circuit, the second chamber oil circuit and the third chamber oil circuit respectively through opening and closing actions.

Further, a third relief valve connected to the oil tank is arranged in parallel on the oil circuit of the third chamber, and the third relief valve is configured to be able to Let the oil flow into the oil tank from the third cavity.

Further, the controller is electrically connected to the first motor driver and the second motor driver, and the first motor driver and the second motor driver are respectively electrically connected to the first bidirectional variable speed servo motor and the second bidirectional variable speed servo motor. The speed servo motor, the first bidirectional variable speed servo motor and the second bidirectional variable speed servo motor are adapted to provide speed feedback and current feedback to the first motor driver and the second motor driver respectively.

Beneficial effect:

1. The system uses an electric energy storage unit and a two-way variable speed servo motor for drive and energy recovery. The two-way variable speed servo motor is connected to the two-way hydraulic pump motor to control the flow and pressure, and the forward and reverse rotation of the motor is controlled by the controller and the motor driver. To control the extension and retraction of the symmetrical hydraulic cylinder actuator, the extension and retraction speed of the symmetrical hydraulic cylinder actuator is controlled by the controller and the motor driver to control the forward and reverse speed of the motor.

2. The asymmetric cylinder used in this system is equipped with a third chamber directly connected to a small pump control system, which can perform independent energy recovery and load force drive control on the asymmetric cylinder according to the working conditions. The energy exchange between the servo motor and the electric energy storage unit can be realized through the identification of the parallel load condition and the reverse load condition and the separate control of the two servo motors, so as to realize energy recovery and utilization, and can also better match Load force output in working condition. Different from the traditional closed pump-controlled asymmetric cylinder system, the new closed pump-controlled asymmetric cylinder system solves the flow compensation problem existing in the traditional asymmetric cylinder closed pump control system by using a three-chamber hydraulic cylinder, and can pass The small closed pump control system actively controls the pressure of the third chamber, assists in controlling the energy recovery and actuation of the asymmetric cylinder, and has greatly improved energy utilization efficiency, actuation speed and output force.

Description of drawings

Fig. 1 is a novel closed pump control asymmetric cylinder system and its control schematic diagram of the embodiment of the present invention;

Icons: electric energy storage unit 1, first two-way variable speed servo motor 2, first two-way hydraulic pump motor 3, fuel tank 4, first one-way valve 5, second one-way valve 6, first overflow valve 7, second Second overflow valve 8, first two-position two-way solenoid valve 9, second two-position two-way solenoid valve 10, third two-position two-way solenoid valve 11, magnetostrictive displacement sensor 12, asymmetric hydraulic cylinder 13, the third two-position two-way solenoid valve Four-two-position two-way solenoid valve 14 , a third relief valve 15 , a second bidirectional hydraulic pump motor 16 , a second bidirectional variable speed servo motor 17 , a second motor driver 18 , a first motor driver 19 , and a controller 20 .

Detailed ways

Example

With reference to Fig. 1, this embodiment provides a new type of closed-type pump-controlled asymmetric cylinder system for electric construction machinery, including an electric energy storage unit 1, a fuel tank 4, and also includes: a first two-way variable speed servo motor 2, a first two-way Hydraulic pump motor 3, asymmetric hydraulic cylinder 13, second bidirectional hydraulic pump motor 16, second bidirectional variable speed servo motor 17, first motor driver 19, second motor driver 18 and controller 20; wherein, the asymmetric The hydraulic cylinder 13 is suitable for connecting the external load of the system, which includes a first chamber, a second chamber and a third chamber;

The first two-way hydraulic pump motor 3 includes a first oil port and a second oil port, and the first oil port communicates with the first cavity of the asymmetric hydraulic cylinder 13 to form a first cavity oil circuit, and the second oil port communicates with the first cavity of the asymmetric hydraulic cylinder 13, and the second oil port communicates with the first cavity of the asymmetric hydraulic cylinder 13. The second chamber of the asymmetric hydraulic cylinder 13 is connected to form a second chamber oil passage, the third chamber of the asymmetric hydraulic cylinder 13 is connected to the second bidirectional hydraulic pump motor 16 to form a third chamber oil passage, and the first Two bidirectional hydraulic pump motors 16 are connected to the second bidirectional variable speed servo motor 17, and the second bidirectional variable speed servo motor 17 is electromechanically connected to the second motor driver 18; the first bidirectional variable speed servo motor 2 It is configured to be able to control the actuating direction and actuating speed of the asymmetric hydraulic cylinder 13 by controlling the flow and pressure of the first bidirectional hydraulic pump motor 3;

The electric energy storage unit 1 is simultaneously connected to the first bidirectional variable speed servo motor 2 and the second bidirectional variable speed servo motor 17, and is configured such that when the external load of the system is in a parallel load condition, the first bidirectional variable speed servo motor The servo motor 2, the second two-way variable speed servo motor 17, the first two-way hydraulic pump motor 3, and the second two-way hydraulic pump motor 16 can rotate under the action of an external load to generate electricity to the electric energy storage unit 1 for energy recovery storage; when the external load of the system is in reverse load condition, the electric energy storage unit 1 can supply power to the controller 20 and the motor driver to drive the first bidirectional variable speed servo motor 2 and the second bidirectional variable speed servo motor The motor 17 rotates; at this time, the controller 20 and the second motor driver 18 are configured to drive the second bidirectional variable speed servo motor 17 to drive the second bidirectional hydraulic pump motor according to the working conditions of the external load of the system The rotation of 16 gives pressure to the third cavity of the asymmetric cylinder, so as to realize the large load output of the asymmetric hydraulic cylinder 13.

In this embodiment, the electric construction machine may be an excavator, a lift, etc. For convenience of description, this embodiment takes an excavator as an example, but is not limited to the excavator.

In this embodiment, the asymmetric hydraulic cylinder 13 also includes a magnetostrictive displacement sensor 12 and an extension rod, the extension rod is movably connected to the first chamber and the third chamber, and is suitable for connecting with the electric The construction machinery is connected to bear the external load of the system; the magnetostrictive displacement sensor 12 is connected to the controller 20 and the extension rod, and is configured to collect displacement data of the extension rod and transmit the data to the controller 20. The protruding rod described here is used to carry the load, and its working principle is as follows:

When the extension rod of the asymmetric hydraulic cylinder 13 extends upwards and the load force is upwards, the first bidirectional variable speed servo motor 2 is in the load condition (for example, the arm of the excavator is in contact with the ground to support the body and slowly falls), The first chamber of the asymmetric hydraulic cylinder 13 is a high-pressure chamber, and the second chamber is a low-pressure chamber. The extension rod of the asymmetric hydraulic cylinder 13 extends upwards. The hydraulic pump motor 3 flows to the second cavity and simultaneously drives the first bidirectional hydraulic pump motor 3 and the first bidirectional variable speed servo motor 2 to rotate forward to generate electricity for the electric energy storage unit 1 to complete the recovery of electrical energy. The second two-way variable speed servo motor 17 is also in the load condition at this time, and the oil flows from the oil tank 4 through the second two-way hydraulic pump motor 16 into the third cavity of the asymmetric hydraulic cylinder 13 under the action of the external load of the system, driving The second two-way hydraulic pump motor 16 and the second variable speed servo motor rotate forward to generate electricity for the electric energy storage unit 1 to complete energy recovery and storage.

When the asymmetrical hydraulic cylinder 13 stretches out the rod and retracts downward and the received load force is upward, the first bidirectional variable speed servo motor 2 is in the reverse load condition (for example, the arm of the excavator is in contact with the ground and the support body is slowly lifted or The arm of the excavator is in contact with the ground and digs downward), at this time, the first chamber of the asymmetric hydraulic cylinder 13 is a high-pressure chamber, the second chamber is a low-pressure chamber, and the electric energy storage unit 1 supplies power to the controller 20 and the first motor Under the control of the driver 19, the first two-way variable speed servo motor 2 and the first two-way hydraulic pump motor 3 are driven to rotate in reverse so that the oil flows from the second chamber to the first chamber through the first two-way hydraulic pump motor 3 to push the asymmetrical hydraulic cylinder 13 The extension rod retracts downward. The second two-way variable speed servo motor 17 is also in the reverse load mode at this time, and the electric energy storage unit 1 supplies power to drive the second two-way variable speed servo motor 17 and the second two-way hydraulic pressure under the control of the controller 20 and the second motor driver 18. The pump motor 16 rotates in the opposite direction, and the oil flows from the third chamber of the asymmetric hydraulic cylinder 13 through the second two-way hydraulic pump motor 16 into the oil tank 4 under the action of the second two-way hydraulic pump motor 16, and the auxiliary asymmetric hydraulic cylinder 13 extends The rod is retracted downward;

When the extension rod of the asymmetrical hydraulic cylinder 13 is retracted downwards and the received load force is downwards, the first two-way variable speed servo motor 2 is in the load condition (for example, the excavator arm is driven by from high to low), at this time, the first chamber of the asymmetric hydraulic cylinder 13 is a low-pressure chamber, and the second chamber is a high-pressure chamber. Under the action of the second chamber, the first two-way hydraulic pump motor 3 flows to the first chamber, and at the same time drives the first two-way hydraulic pump motor 3 and the first two-way variable speed servo motor 2 to rotate in reverse to generate electricity for the electric energy storage unit 1 to complete the electrical energy. recycling. The second two-way variable speed servo motor 17 is also in the forward load condition at this time, and the oil flows from the third chamber of the asymmetric hydraulic cylinder 13 through the second two-way hydraulic pump motor 16 and enters the oil tank 4 under the action of the external load of the system, driving the first The two-way hydraulic pump motor 16 and the second variable speed servo motor reversely rotate to generate electricity for the electric energy storage unit 1 to complete energy recovery and storage;

When the extension rod of the asymmetric hydraulic cylinder 13 extends upwards and the load force is downward, the first two-way variable speed servo motor 2 is in the reverse load condition (for example, the excavator arm changes from low to high under no load or load state). lifting), the first chamber of the asymmetric hydraulic cylinder 13 is a low-pressure chamber, the second chamber is a high-pressure chamber, and the electric energy storage unit 1 supplies power to drive the first two-way variable speed servo drive under the control of the controller 20 and the first motor driver 19 The motor 2 and the first two-way hydraulic pump motor 3 rotate forward to make the oil flow from the first chamber to the second chamber through the first two-way hydraulic pump motor 3 to push the extension rod of the asymmetric hydraulic cylinder 13 to extend upward. At this time, the second bidirectional variable speed servo motor 17 is also in the reverse load condition, and the electric energy storage unit 1 supplies power to drive the second bidirectional variable speed servo motor 17 and the second motor driver 18 under the control of the controller 20 and the second motor driver 18. The second two-way hydraulic pump motor 16 rotates in the forward direction, and the oil flows from the oil tank 4 through the second two-way hydraulic pump motor 16 into the third cavity of the asymmetric hydraulic cylinder 13 under the action of the second two-way hydraulic pump motor 16, assisting the asymmetric hydraulic cylinder 13 Extend the lever upwards.

In the embodiment of the present invention, a small closed pump control system is provided, and the small closed pump control system includes the fourth two-position two-way solenoid valve 14, the third overflow valve 15, and the second two-way hydraulic pump motor 16. , the second bidirectional variable speed servo motor 17 and the second motor driver 18. The third overflow valve 15 is arranged in parallel on the oil circuit of the third chamber, and is connected to the oil tank 4. The third overflow valve 15 is configured to overload the pressure in the third chamber of the asymmetric hydraulic cylinder 13. Oil can flow into the oil tank 4 from the third cavity. The third chamber of the asymmetric hydraulic cylinder 13 is directly connected to the small closed pump control system. When the pressure in the third chamber of the asymmetric hydraulic cylinder 13 is overloaded, the third overflow valve 15 works to let the oil flow from the third chamber of the asymmetric hydraulic cylinder 13. According to the forward load and reverse load conditions, the controller 20 and the second motor driver 18 will jointly control the speed, steering and power generation of the second bidirectional variable speed servo motor 17 and the second bidirectional hydraulic pump motor 16 .

In this embodiment, the first one-way valve 5 and the second one-way valve connected to the oil tank 4 are arranged in parallel on the first chamber oil circuit and the second chamber oil circuit of the first two-way hydraulic pump motor 3 respectively. 6, and a first relief valve 7 and a second relief valve 8 connected to the oil tank 4 are arranged in parallel on the first one-way valve 5 and the second one-way valve 6 respectively. When the excavator arm is extended (retracted) to the maximum position or the load is too large and the internal pressure of the new closed pump control asymmetric cylinder system is too high, the oil will flow through the first overflow valve 7 and the second overflow The valve 8 flows into the oil tank 4 to realize the overload protection of the system and prevent the system and components from being damaged; at the same time, when the internal flow of the new closed pump-controlled asymmetric cylinder system is insufficient, the hydraulic oil in the oil tank 4 will pass through the first one-way valve 5 and the second The one-way valve 6 flows into the system so as to supplement the first chamber or the second chamber of the asymmetric hydraulic cylinder 13 with oil.

The first two-way hydraulic pump motor 3 is also provided with a first two-position two-way solenoid valve 9 in parallel, and the first two-position two-way solenoid valve 9 is arranged in the first cavity oil circuit of the asymmetric hydraulic cylinder 13 Between and the second cavity oil circuit and in the normally closed position. When the excavator is used up or the new closed-type pump-controlled asymmetric cylinder system is damaged and cannot work normally, the first two-position two-way solenoid valve 9 can be actively controlled to unload the asymmetric hydraulic cylinder 13 so that the asymmetric hydraulic cylinder 13 The extension rod returns to the initial position, and the pressure balance between the first cavity and the second cavity of the asymmetric hydraulic cylinder 13 is controlled to prevent system damage.

In a preferred embodiment, the second two-position two-way solenoid valve 10 is provided on the oil circuit of the first chamber and is in the normally open position, and the third two-position two-way solenoid valve 11 is provided on the oil circuit of the second chamber and is in the normal open position. In the normally open position, the fourth two-position two-way solenoid valve 14 is provided on the oil circuit of the third cavity and is in the normally open position; the second two-position two-way solenoid valve 10, the third two-position two-way solenoid valve 11, The fourth two-position two-way solenoid valve 14 is configured to be able to switch on and off of the oil circuit in the first chamber, the oil circuit in the second chamber and the oil circuit in the third chamber through opening and closing actions respectively. When the power is cut off, the asymmetric hydraulic cylinder 13 is fully connected with the first cavity oil circuit, the second cavity oil circuit and the small closed pump control system to ensure that the new closed pump control asymmetric cylinder system can work normally. When the excavator arm needs to hover at a certain position due to working conditions, the system supplies power to the second two-position two-way solenoid valve 10, the third two-position two-way solenoid valve 11, and the fourth two-position two-way solenoid valve 14. Simultaneously switch to the closed position to cut off the first cavity oil circuit, the second cavity oil circuit and the small pump control system to keep the asymmetric hydraulic cylinder 13 in a pressure maintaining state.

The controller 20 is electrically connected to the first motor driver 19 and the second motor driver 18, and the first motor driver 19 and the second motor driver 18 are electrically connected to the first bidirectional variable speed servo motor 2 and the second motor driver 2 respectively. Two bidirectional variable speed servo motors 17, the first bidirectional variable speed servo motor 2 and the second bidirectional variable speed servo motor 17 are suitable for providing speed feedback and current feedback to the first motor driver 19 and the second motor driver 18 respectively .

The new closed pump-controlled asymmetric cylinder system mainly controls the actuating direction and actuating speed of the asymmetric hydraulic cylinder 13 by controlling the steering and rotating speed of the first bidirectional variable speed servo motor 2 and the second bidirectional variable speed servo motor 17 . The control system of the novel closed pump control asymmetric cylinder system includes a controller 20, a first motor driver 19, and a second motor driver 18, and a target signal is input to the controller 20, and the controller 20 will automatically analyze and process the data to the first motor driver 18. The motor driver 19 and the second motor driver 18 control the steering and rotating speed of the first bidirectional variable speed motor and the second bidirectional variable speed motor, and collect displacement and speed according to the magnetostrictive displacement sensor 12 installed on the asymmetric hydraulic cylinder 13 The signal feeds back data to the controller 20 to complete the negative feedback control. The controller 20 will individually control the first bidirectional variable speed servo motor 2 and the second bidirectional variable speed servo motor 17 according to the working conditions and working modes of the excavator to achieve the best working performance.

The new closed-type pump-controlled asymmetric cylinder system in the embodiment of the present invention can recover the energy of the system under the parallel load condition, and generate electricity for the electric energy storage unit 1 through the bidirectional hydraulic pump motor and the bidirectional variable speed servo motor for energy storage. Under the reverse load condition, the electric energy storage unit 1 supplies power to the bidirectional variable speed servo motor and the bidirectional hydraulic pump motor for energy utilization. At the same time, the asymmetric hydraulic cylinder 13 of the system has a third hydraulic chamber directly connected to a small closed pump control system, which can recover and utilize energy through independent control, and can independently drive the small closed pump control system to actively control according to the working conditions The flow and pressure assist in controlling the actuators of the asymmetric hydraulic cylinder 13 to improve the performance of the system. Through the invention, the energy utilization efficiency of the boom of the electric construction machinery is improved, the energy wasted in the working process is recovered and utilized, and the load capacity and working performance of the boom are improved at the same time.

It should be understood that: the above are only preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above examples, and all technical solutions under the idea of the present invention belong to the scope of protection of the present invention.

The above description of the drawings used in the implementation mode only shows some embodiments of the present invention, and should not be regarded as limiting the scope. Under the premise, other related drawings can also be obtained based on these drawings.

Claims (7)

1. The utility model provides a novel asymmetric jar system of closed pump accuse of electric engineering machinery, includes electric energy storage unit, oil tank, its characterized in that still includes: the system comprises a first bidirectional variable speed servo motor, a first bidirectional hydraulic pump motor, an asymmetric hydraulic cylinder, a second bidirectional hydraulic pump motor, a second bidirectional variable speed servo motor, a first motor driver, a second motor driver and a controller; wherein,,

the asymmetric hydraulic cylinder is suitable for being connected with an external load of a system and comprises a first cavity, a second cavity and a third cavity;

the first bidirectional hydraulic pump motor comprises a first oil port and a second oil port, the first oil port is communicated with the first cavity of the asymmetric hydraulic cylinder to form a first cavity oil way, the second oil port is communicated with the second cavity of the asymmetric hydraulic cylinder to form a second cavity oil way, the third cavity of the asymmetric hydraulic cylinder is communicated with the second bidirectional hydraulic pump motor to form a third cavity oil way, the second bidirectional hydraulic pump motor is connected to the second bidirectional variable-rotation-speed servo motor, and the second bidirectional variable-rotation-speed servo motor is electrically connected to the second motor driver;

the first bidirectional variable-rotation-speed servo motor is configured to control the actuation direction and the actuation speed of the asymmetric hydraulic cylinder by controlling the flow and the pressure of the first bidirectional hydraulic pump motor;

the electric energy storage unit is connected with the first bidirectional variable speed servo motor and the second bidirectional variable speed servo motor at the same time, and is configured to enable the first bidirectional variable speed servo motor, the second bidirectional variable speed servo motor, the first bidirectional hydraulic pump motor and the second bidirectional hydraulic pump motor to rotate under the action of external load so as to generate electricity for the electric energy storage unit to recover and store energy when external load of the system is in a forward load working condition; when the external load of the system is in a reverse load working condition, the electric energy storage unit can supply power to the controller, the first motor driver and the second motor driver to drive the first bidirectional variable-speed servo motor and the second bidirectional variable-speed servo motor to rotate; at this time, the controller and the second motor driver are configured to drive the second bidirectional variable rotation speed servo motor to drive the second bidirectional hydraulic pump motor to rotate according to the working condition of the external load of the system so as to give the third cavity pressure of the asymmetric cylinder, thereby realizing the heavy load output of the asymmetric hydraulic cylinder.

2. The novel closed pump controlled asymmetric cylinder system of an electric engineering machine of claim 1, wherein the asymmetric hydraulic cylinder further comprises a magnetostrictive displacement sensor and an extension rod, the extension rod is movably connected to the first cavity and the third cavity and is suitable for being connected with the electric engineering machine to bear external load of the system; the magnetostrictive displacement sensor is coupled to the controller and the extension rod and is configured to collect displacement data of the extension rod and transmit the data to the controller.

3. The novel closed pump-controlled asymmetric cylinder system of an electric engineering machine according to claim 1, wherein a first check valve and a second check valve which are communicated to the oil tank are respectively arranged on a first cavity oil path and a second cavity oil path of the first bidirectional hydraulic pump motor in parallel, and a first overflow valve and a second overflow valve which are communicated to the oil tank are respectively arranged on the first check valve and the second check valve in parallel.

4. The novel closed pump-controlled asymmetric cylinder system of an electric engineering machine as claimed in claim 3, wherein the first bi-directional hydraulic pump motor is further provided with a first two-position two-way solenoid valve in parallel, and the first two-position two-way solenoid valve is configured between a first cavity oil path and a second cavity oil path of the asymmetric hydraulic cylinder and is in a normally closed position.

5. The novel closed pump control asymmetric cylinder system of the electric engineering machinery according to claim 1, wherein a second two-position two-way electromagnetic valve is arranged on the first cavity oil path and is in a normally open position, a third two-position two-way electromagnetic valve is arranged on the second cavity oil path and is in a normally open position, and a fourth two-position two-way electromagnetic valve is arranged on the third cavity oil path and is in a normally open position; the second two-position two-way electromagnetic valve, the third two-position two-way electromagnetic valve and the fourth two-position two-way electromagnetic valve are configured to be capable of switching on and off of the first cavity oil way, the second cavity oil way and the third cavity oil way through opening and closing actions respectively.

6. The novel closed pump-controlled asymmetric cylinder system of an electric engineering machine of claim 1, wherein a third relief valve is further disposed in parallel on the third chamber oil path and is configured to allow oil to flow from the third chamber into the oil tank when the third chamber of the asymmetric hydraulic cylinder is pressure-overloaded.

7. The novel closed pump controlled asymmetric cylinder system of an electric work machine of claim 1, wherein the controller is electrically connected to the first and second motor drivers, the first and second motor drivers being electrically connected to the first and second bi-directional variable speed servomotors, respectively, the first and second bi-directional variable speed servomotors being adapted to provide speed feedback and current feedback to the first and second motor drivers, respectively.

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