CN108591144B - Distributed direct-drive excavator hydraulic system with motor-driven dual quantitative pumps and dual accumulators - Google Patents

Abstract

The invention provides a motor-driven double-dosing pump double-accumulator distributed direct-drive excavator hydraulic system, which is characterized in that a signal is input to a driver through a controller, and the rotation speed and the direction of a driving motor in each hydraulic module are controlled through the driver to control a hydraulic cylinder, so that the throttle loss and overflow loss of the system are avoided, the system efficiency is high, a main loop is shorter and no throttle element exists, therefore, the pressure loss is less, the heating value is less, and a cooling device is not needed; simultaneously adopting two energy accumulators, wherein the second energy accumulator is used for replacing an oil tank; the first energy accumulator is used for balancing the flow of the first chamber and the second chamber when the displacement ratio of the two quantitative pumps is inconsistent with the effective area ratio of the two chambers of the hydraulic cylinder, and solves the problem that the displacement ratio of the two quantitative pumps cannot be accurately matched with the effective area ratio of the two chambers of the hydraulic cylinder.

Description

Distributed direct-drive excavator hydraulic system with motor-driven dual quantitative pumps and dual accumulators

technical field

The invention relates to the field of excavators, in particular to a hydraulic system of the excavator.

Background technique

As the most commonly used machinery in construction machinery, hydraulic excavators have the disadvantages of high fuel consumption, poor emissions, and low energy utilization. Under the situation of energy shortage and environmental pollution becoming more and more serious, how to realize the energy saving and emission reduction of excavators has attracted more and more attention, and has become a hot research topic at present.

The current excavator still uses the driving system of engine-variable pump-multi-way valve-actuator. Due to the requirements of energy saving and environmental protection, some studies have used ordinary motors to replace engines, but the system efficiency still needs to be improved. With the successive development of AC servo motors, servo motors-quantitative hydraulic pumps/motors-hydraulic valves-actuators have been used in engineering applications, such as injection molding machines. These hydraulic system energy saving methods play an important role in improving efficiency.

Invention patent CN201110453095 "An all-electric servo excavator" (public date: 2013-07-03) adopts an electric-mechanical drive and servo system combining an AC servo motor and a ball screw. Its advantages are that electric energy is directly converted into mechanical energy, the system is simple, consumes less energy, and occupies a small space. However, when low-speed, high-torque, and high-efficiency working conditions are required, this kind of motor-machine transmission and servo system needs to add a reducer to complete the transmission task, which makes the system complicated, and sometimes even adding a reducer still cannot meet the requirements.

Invention patent CN201610406357 "All-electric drive hydraulic excavator power system" (public date: 2016-10-12), controls the speed and direction of each servo motor, thereby controlling the size and direction of the output flow of the bidirectional quantitative pump connected to it, and finally completes the speed control of each hydraulic actuator. ①The system uses a servo motor to drive a two-way quantitative pump to control a symmetrical hydraulic cylinder. The effective area on the piston side of the hydraulic cylinder is reduced, so that the output force is greatly reduced when the piston is extended. ②When the system pressure is high, the torque required to drive the fixed displacement pump is relatively large, which requires high performance of the motor, for example, a wide range of torque and power. ③The system cannot recover the energy fed back by negative loads.

Contents of the invention

The technical problem to be solved by the present invention is to provide a distributed direct-drive excavator hydraulic system with motor-driven dual quantitative pumps and dual accumulators, which avoids throttling loss and overflow loss of the system, has high system efficiency, and realizes energy saving, emission reduction and noise reduction.

The present invention is realized in the following way: the hydraulic system of the distributed direct-drive excavator with motor-driven double quantitative pumps and double accumulators includes a controller and at least one hydraulic module; each hydraulic module includes a hydraulic cylinder, a first bidirectional quantitative pump, a second bidirectional quantitative pump, a first accumulator, a second accumulator, a three-position three-way control valve, a driver, and a drive motor;

The hydraulic cylinder includes a cylinder, a piston and a piston rod, one end of the piston rod is fixedly connected to the piston, the piston is airtight and slidably connected to the cylinder, and the piston divides the cylinder into a first chamber and a second chamber;

The three-position three-way control valve includes a first oil connection port, a first hydraulic control control oil port, a second oil connection port, a second hydraulic control control oil port and a third oil connection port;

The first bidirectional quantitative pump includes a first drain port, a first port and a second port;

The second bidirectional quantitative pump includes a second oil drain port, a third port and a fourth port;

The second port and the fourth port are connected in parallel to the second accumulator; the first port, the first oil connection port and the first hydraulic control control port are connected in parallel to the first chamber; the third port, the second oil connection port and the second hydraulic control control port are connected in parallel to the second chamber; the third oil connection port is connected to the first accumulator;

The first bidirectional quantitative pump and the second bidirectional quantitative pump are respectively connected to the driving motor to realize synchronous movement; the driver is connected to the controller through communication.

Further, a power supply device is also included, and the driver and the controller are respectively electrically connected to the power supply device.

Further, each hydraulic module further includes a first control valve and a second control valve, the first port, the first oil connection port and the first hydraulic control control port are connected in parallel and sequentially connected to the first control valve and the first chamber; the third port, the second oil connection port and the second hydraulic control control port are connected in parallel and sequentially connected to the second control valve and the second chamber; the first control valve and the second control valve are also connected to the controller through communication.

Further, the first control valve and the second control valve are respectively two-position two-way solenoid valves.

Further, the first control valve and the second control valve are respectively two-position two-way cartridge valves.

Further, each hydraulic module further includes a first one-way valve, a second one-way valve, a first safety valve and a second safety valve;

The inlet of the first one-way valve and the outlet of the first safety valve are connected in parallel to the second port, and the outlet of the first one-way valve and the inlet of the first safety valve are connected in parallel and connected between the first control valve and the first chamber;

The inlet of the second one-way valve and the outlet of the second safety valve are connected in parallel to the second accumulator, and the outlet of the second one-way valve and the inlet of the second safety valve are connected in parallel and connected between the second control valve and the second chamber.

Further, the three-position three-way control valve is a three-position three-way hydraulic control valve.

Further, the three-position three-way control valve is a three-position three-way cartridge valve.

Further, the driving motor is a servo motor, and the driver is a servo driver.

Further, the number of the hydraulic modules is three.

The present invention has the following advantages: the present invention inputs signals to the driver through the controller, and then controls the speed and direction of the drive motor in each hydraulic module through the driver to realize the control of the hydraulic cylinder, avoiding the throttling loss and overflow loss of the system, the system efficiency is high, the main circuit is very short and there is no throttling element, so the pressure loss is small and the heat generation is small, and no cooling device is used. Two accumulators are used at the same time, wherein the second accumulator is used to replace the oil tank; When the ratio is inconsistent with the effective area ratio of the first chamber and the second chamber, it is used to balance the flow of the first chamber and the second chamber, and solves the problem that the displacement ratio of the first bidirectional quantitative pump and the second bidirectional quantitative pump cannot accurately match the effective area ratio of the first chamber and the second chamber.

Description of drawings

The present invention will be further described below in conjunction with the embodiments with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of an embodiment of the hydraulic system of the present invention.

Fig. 2 is a schematic diagram of the oil operation of the hydraulic module in the first working condition according to the present invention.

Fig. 3 is a schematic diagram of the operation principle of the hydraulic module in the second working condition of the hydraulic module according to the present invention.

Fig. 4 is a schematic diagram of the operation principle of the oil in the hydraulic module according to the present invention in the third working condition.

Fig. 5 is a schematic diagram of the operation principle of the oil in the hydraulic module according to the present invention in working condition four.

Fig. 6 is a schematic diagram of the operation principle of oil in the hydraulic module according to the present invention in working condition five.

Fig. 7 is a schematic diagram of the operation principle of the oil in the hydraulic module of the present invention under working condition six.

Fig. 8 is a schematic diagram of the operation principle of the oil in the hydraulic module according to the present invention in working condition 7.

Fig. 9 is a schematic diagram of the operation principle of the hydraulic module of the present invention in working condition eight.

Fig. 10 is a schematic diagram of the effect of the present invention.

In the figure: 100, controller; 200, hydraulic module; 201, hydraulic cylinder; 2011, cylinder body; 2012, piston; 2013, piston rod; 202, first bidirectional quantitative pump; 2021, first port; 2022, second port; 205, the second accumulator; 206, the three-position three-way control valve; 2061, the first oil connection port; 2062, the first hydraulic control control oil port; 2063, the second oil connection port; 2064, the second hydraulic control control oil port; 2065, the third oil connection port; Valve; 213, first safety valve; 214, second safety valve; 300, boom; 400, stick; 500, bucket; 600, power supply unit; 700, first chamber; 800, second chamber.

Detailed ways

1 to 10, the present invention provides a distributed direct-drive excavator hydraulic system with motor-driven double constant pumps and double accumulators, including a controller 100 and at least one hydraulic module 200; each hydraulic module 200 includes a hydraulic cylinder 201, a first bidirectional quantitative pump 202, a second bidirectional quantitative pump 203, a first accumulator 204, a second accumulator 205, a three-position three-way control valve 206, a driver 207 and a drive motor 208;

The hydraulic cylinder 201 includes a cylinder body 2011, a piston 2012 and a piston rod 2013, one end of the piston rod 2013 is fixedly connected to the piston 2012, the piston 2012 is airtightly and slidably connected to the cylinder body 2011, and the piston 2012 divides the interior of the cylinder body 2011 into a first chamber 700 and a second chamber 800;

The three-position three-way control valve 206 includes a first oil connection port 2061, a first hydraulic control control port 2062, a second oil connection port 2063, a second hydraulic control control port 2064 and a third oil connection port 2065;

The first bidirectional quantitative pump 202 includes a first drain port 2023, a first port 2021 and a second port 2022;

The second bidirectional quantitative pump 203 includes a second oil drain port 2033, a third port 2031 and a fourth port 2032;

The second port 2022 and the fourth port 2032 are connected in parallel to the second accumulator 205; the first port 2021, the first oil connection port 2061 and the first hydraulic control control port 2062 are connected in parallel to connect to the first chamber 700; the third port 2031, the second oil connection port 2063 and the second hydraulic control control port 2064 are connected in parallel to the second chamber 800; the third oil connection port 2065 is connected to the first accumulator The energy device 204; the first oil drain port 2023 is connected between the second port 2022 and the fourth port 2032, and the second oil drain port 2033 is connected between the fourth port 2032 and the second accumulator 205, which can prevent the first bidirectional quantitative pump 202 or the second bidirectional quantitative pump 203 from being overpressured and cause the shell to rupture, thereby ensuring safety;

The first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203 are respectively connected to the drive motor 208 to realize synchronous movement; the driver 207 is connected to the controller 100 by communication.

In a specific implementation, the hydraulic cylinder 201 is an asymmetric hydraulic cylinder 201, and the piston rod 2013 is connected to an applied load. In the present invention, the controller 100 inputs signals to the driver 207, and then controls the rotational speed and direction of the drive motor 208 in each hydraulic module 200 through the driver 207, and then controls the flow rate and flow direction of the first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203, and finally realizes the control of the hydraulic cylinder 201.

The first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203 are directly connected to the driving motor 208 to independently drive the hydraulic cylinder 201, which not only realizes the basic matching of the flow rates of the first chamber 700 and the second chamber 800, but also avoids throttling loss and overflow loss, and the system efficiency is high.

The distributed intelligent control of power transmission by wires instead of hydraulic pipelines makes the main circuit of the invention very short and has no throttling elements, so the pressure loss is small, the calorific value is small, and no cooling device is needed.

Compared with the traditional hydraulic system, the present invention adopts a closed system that uses less oil, and the required volumes of the first accumulator 204 and the second accumulator 205 are small, and each hydraulic module 200 can be made into a hydraulic pack.

The drive motor 208 is used to replace the engine-driven variable pump in the traditional technology, the system efficiency is greatly improved, and energy saving, emission reduction and noise reduction are realized. After the traditional system starts to work, the actuator will not stop even if it is not working, and the motor and oil pump will run as usual, which consumes a lot of energy. In the present invention, when the hydraulic cylinder 201 needs to work, the driving motor 208 runs, and when the hydraulic cylinder 201 does not work, the driving motor 208 stops, so as to realize on-demand driving and save electric energy.

The present invention adopts two accumulators, wherein the second accumulator 205 is used to replace the oil tank, and because the hydraulic cylinder 201 is an asymmetric hydraulic cylinder 201, the first chamber 700 and the second chamber 800 have an effective area difference, and the second accumulator 205 also plays the role of balancing flow; When the effective area ratio is inconsistent, it is used to balance the flow of the first chamber 700 and the second chamber 800, solving the problem that the displacement ratio of the first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203 cannot accurately match the effective area ratio of the first chamber 700 and the second chamber 800.

And in a specific implementation, the first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203 can be used as a pump and a motor respectively. At this time, the present invention also provides conditions for recycling the potential energy fed back by the load.

In a specific implementation, a preferred embodiment further includes a power supply device 600, the driver 207 and the controller 100 are respectively electrically connected to the power supply device 600, and in the case of a negative load, the first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203 are used as motors, and the potential energy fed back by the load at this time can be converted into electrical energy and stored in the power supply device 600, so as to realize the energy recovery and utilization of negative load and save electric energy.

Each hydraulic module 200 also includes a first control valve 209 and a second control valve 210, the first port 2021, the first oil connection port 2061 and the first hydraulic control control port 2062 are connected in parallel and then connected to the first control valve 209 and the first chamber 700; The first control valve 209 and the second control valve 210 are also communicatively connected to the controller 100 , and the controller 100 controls the opening or closing of the first control valve 209 and the second control valve 210 . The hydraulic cylinder 201 is locked by the first control valve 209 and the second control valve 210 to avoid sliding caused by the leakage of the first bidirectional quantitative pump 202 or the second bidirectional quantitative pump 203 .

The first control valve 209 and the second control valve 210 are respectively two-position two-way solenoid valves. When the flow rate is small, a two-position two-way solenoid valve is used, which is mainly used in miniature excavators in practical applications.

The first control valve 209 and the second control valve 210 are respectively two-position two-way cartridge valves. Two-position two-way cartridge valves are used for large flows, and are mainly used in small, medium and large excavators in practical applications.

Each hydraulic module 200 also includes a first one-way valve 211, a second one-way valve 212, a first safety valve 213 and a second safety valve 214;

The inlet of the first one-way valve 211 and the outlet of the first safety valve 213 are connected in parallel to the second port 2022, and the outlet of the first one-way valve 211 and the inlet of the first safety valve 213 are connected in parallel and connected between the first control valve 209 and the first chamber 700;

The inlet of the second one-way valve 212 and the outlet of the second safety valve 214 are connected in parallel to the second accumulator 205 , and the outlet of the second one-way valve 212 and the inlet of the second safety valve 214 are connected in parallel and connected between the second control valve 210 and the second chamber 800 . Through the combination of the first one-way valve 211 and the first safety valve 213, or the combination of the second one-way valve 212 and the second safety valve 214, the phenomenon of cavitation is prevented at low pressure, and the pressure is released at high pressure, so that excess oil is stored in the second accumulator 205, specifically, when the pressure of the first chamber 700 or the second chamber 800 is low, the corresponding first one-way valve 211 or second one-way valve 212 conducts, and the oil flows from the second accumulator 20 5 in the first chamber 700 or the second chamber 800; when the pressure of the first chamber 700 or the second chamber 800 is too high, the corresponding first safety valve 213 or the second safety valve 214 is turned on at this time to release the pressure, and the excess oil flows into the second accumulator 205 to ensure safety.

The three-position three-way control valve 206 is a three-position three-way hydraulic control valve.

The three-position three-way control valve 206 is a three-position three-way cartridge valve.

The driving motor 208 is a servo motor 208, and the driver 207 is a servo driver 207, which can make the control speed very accurate.

The number of the hydraulic modules 200 is three. The piston rods 2013 of the three hydraulic modules 200 are respectively connected to the boom 300, stick 400, and bucket 500 of the excavator in one-to-one correspondence, so that the three can be driven independently, which is convenient for control, and at the same time greatly shortens the pipeline. The hydraulic module 200 can be made into a hydraulic package and directly installed near the boom 300, stick 400, and bucket 500.

Specific control principle:

Because of the existence of the piston rod 2013, the first chamber 700 and the second chamber 800 have an asymmetric structure, so that the maximum volume of the first chamber 700 is larger than the maximum volume of the second chamber 800, and the hydraulic cylinder 201 is an asymmetric hydraulic cylinder 201. When the oil is transferred from the first chamber 700 to the second chamber 800, there is excess oil, and the excess oil needs to be stored in the second accumulator 205. When the chamber 800 is delivered to the first chamber 700 , the oil in the second accumulator 205 needs to be replenished into the first chamber 700 .

On the other hand, in Fig. 2 to Fig. 9, F is the external force applied by the load on the piston rod 2013, and v is the operating speed of the piston rod 2013; the direction of the hydraulic pressure is opposite to that of the external force F; the piston rod 2013 is connected to the load of the excavator, and the load of the excavator will generate potential energy during operation; the first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203 can be used as pumps or as motors to generate electricity;

Positive load: the direction of the hydraulic pressure is the same as the direction of v, the piston rod 2013 extends or retracts, at this time the power supply device 600 outputs electric energy, the controller 100 controls the driver 207 to drive the servo motor 208 to drive the first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203 to rotate according to the speed and direction set by the controller, and the piston rod 2013 outputs energy to the load;

Negative load: the direction of the hydraulic pressure is opposite to the direction of v, the piston rod 2013 is extended or retracted, and the load feeds back energy to the piston rod 2013, through the hydraulic circuit, the first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203 are used as motors to generate electricity, and the energy is stored in the power supply device 600 for recycling;

The displacement of the first bidirectional quantitative pump 202 is marked as _{Vp_a} , the displacement of the second bidirectional quantitative pump 203 is marked as _{Vp_b} , the effective area of the first chamber 700 is marked as _A1 , and the effective area of the second chamber 800 is marked as _A2 ; when _{Vp_b} / _{Vp_a} and _A2 / _A1 do not match, there are the following two situations:

Case 1, V _{p_b} /V _{p_a} is greater than A ₂ /A ₁ ; at this time, there are the following four working conditions:

Working condition 1, please refer to FIG. 2 . At this time, the load is negative, the pressure of the first chamber 700 is greater than the pressure of the second chamber 800, and the oil flows from the second chamber 800 to the first chamber 700. The first hydraulic control oil port 2062 connects the second oil port 2063 of the three-position three-way control valve 206 with the first accumulator 204. At this time, the oil in the first accumulator 204 is replenished to the second chamber 800. Among the outflowing oil, the oil in the second accumulator 205 flows out and is replenished into the first bidirectional quantitative pump 202, and is transported to the first chamber 700 by the first bidirectional quantitative pump 202, so as to realize the flow balance between the first chamber 700 and the second chamber 800. At the same time, the first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203 convert the potential energy fed back by the load into electric energy, and store it in the power supply device 600 for recycling, saving electric energy.

Working condition 2, please refer to FIG. 3 . At this time, the load is positive, the pressure of the second chamber 800 is greater than the pressure of the first chamber 700, and the oil flows from the second chamber 800 to the first chamber 700. The second hydraulic control oil port 2064 connects the first oil connection port 2061 of the three-position three-way control valve 206 with the first accumulator 204. At this time, the oil in the first accumulator 204 is directly replenished to the first chamber 70. 0, the oil in the second accumulator 205 flows out, replenishes into the first bidirectional quantitative pump 202, and is transported to the first chamber 700 by the first bidirectional quantitative pump 202, thereby realizing the flow balance between the first chamber 700 and the second chamber 800, and at this time, the piston rod 2013 outputs energy to the load.

Working condition 3, please refer to FIG. 4 . At this time, the load is positive, the pressure of the first chamber 700 is greater than the pressure of the second chamber 800, the oil flows from the first chamber 700 to the second chamber 800, the oil output by the first bidirectional quantitative pump 202 flows into the second accumulator 205 and the second bidirectional quantitative pump 203 respectively, and the first hydraulic control oil port 2062 connects the second oil connection port 2063 of the three-position three-way control valve 206 Conducting with the first accumulator 204, at this time, part of the output flow of the second bidirectional quantitative pump 203 flows into the first accumulator 204, and another part of oil flows into the second chamber 800, thereby realizing the flow balance between the first chamber 700 and the second chamber 800, and at this time, the piston rod 2013 outputs energy to the load.

Working condition 4, please refer to FIG. 5 , when the load is negative, the pressure of the second chamber 800 is greater than the pressure of the first chamber 700, the oil flows from the first chamber 700 to the second chamber 800, the second hydraulic control oil port 2064 connects the first oil port 201 of the three-position three-way control valve 206 with the first accumulator 204, and part of the oil flowing out of the first chamber 700 passes through the first oil port 2061 It flows into the first accumulator 204, and the other part is delivered to the second bidirectional quantitative pump 203 and the second accumulator 205 by the first bidirectional quantitative pump 202, so as to realize the flow balance in the first chamber 700 and the second chamber 800. At this time, the first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203 convert the potential energy fed back by the load into electrical energy, and store it in the power supply device 600 for recycling, saving electrical energy.

Case 2, V _{p_b} /V _{p_a} is less than A ₂ /A ₁ ; at this time, there are the following four working conditions:

Working condition 5, please refer to FIG. 6 . At this time, the load is negative, the pressure of the first chamber 700 is greater than the pressure of the second chamber 800 , the oil flows from the second chamber 800 to the first chamber 700 , and the first hydraulic control oil port 2062 connects the second oil port 2063 of the three-position three-way control valve 206 with the first accumulator 204 . At this time, a part of the oil flowing out of the second chamber 800 flows into the first accumulator 20 4, the other part flows to the second bidirectional quantitative pump 203 and is delivered to the first bidirectional quantitative pump 202, and the oil in the second accumulator 205 flows out to be replenished in the first bidirectional quantitative pump 202, and is transported to the first chamber 700 by the first bidirectional quantitative pump 202, thereby realizing the flow balance between the first chamber 700 and the second chamber 800, and at the same time, the first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203 convert the potential energy fed back by the load into electrical energy , and stored in the power supply device 600 for recycling, saving electric energy.

Working condition 6, please refer to FIG. 7 . At this time, it is under positive load, the pressure of the second chamber 800 is greater than the pressure of the first chamber 700, the second hydraulic control control oil port 2064 connects the first oil connection port 2061 of the three-position three-way control valve 206 with the first accumulator 204, the oil flows from the second chamber 800 to the first chamber 700, and the oil in the second accumulator 205 is replenished to the first two-way quantitative pump 202 Among them, a part of the oil output by the first bidirectional quantitative pump 202 flows into the first chamber 700, and another part flows into the first accumulator 204 through the first oil connection port 2061, so as to realize the flow balance in the first chamber 700 and the second chamber 800, and at this time, the piston rod 2013 outputs energy to the load.

Working condition 7, please refer to FIG. 8 . At this time, the load is positive, the pressure of the first chamber 700 is greater than the pressure of the second chamber 800, the first hydraulic control oil port 2062 connects the second oil connection port 2063 of the three-position three-way control valve 206 with the first accumulator 204, the oil flows from the first chamber 700 to the second chamber 800, and a part of the oil output by the first bidirectional quantitative pump 202 flows into the second accumulator 205 The other part flows into the second bidirectional quantitative pump 203, and then flows into the second chamber 800. At the same time, the oil in the first accumulator 204 flows into the second chamber 800 through the second oil connection port 2063, so as to realize the flow balance between the first chamber 700 and the second chamber 800. At this time, the piston rod 2013 outputs energy to the load.

Working condition 8, please refer to FIG. 9 . At this time, it is under negative load, the pressure of the second chamber 800 is greater than the pressure of the first chamber 700, and the oil flows from the first chamber 700 to the second chamber 800. The second hydraulic control control oil port 2064 conducts the first oil connection port 2061 of the three-position three-way control valve 206 with the first accumulator 204. At this time, the oil flowing out of the first chamber 700 flows to the first two-way quantitative pump 20 2, and the oil in the first accumulator 204 flows into the first bidirectional quantitative pump 202 from the first oil connection port 2061, a part of the oil output by the first bidirectional quantitative pump 202 flows into the second chamber 800 through the second bidirectional quantitative pump 203, and another part flows into the second accumulator 205, thereby realizing the flow balance between the first chamber 700 and the second chamber 800, and at the same time, the first bidirectional quantitative pump 202 and the second bidirectional quantitative pump 203 return the load to the The fed potential energy is converted into electrical energy and stored in the power supply device 600 for recycling, saving electrical energy.

Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments we have described are only illustrative, and not used to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims (8)

1. The utility model provides a motor drive double-dosing pump double-accumulator's distributed direct drive excavator hydraulic system, includes controller, its characterized in that: the hydraulic system also comprises at least one hydraulic module; each hydraulic module comprises a hydraulic cylinder, a first bidirectional constant displacement pump, a second bidirectional constant displacement pump, a first energy accumulator, a second energy accumulator, a three-position three-way control valve, a driver and a driving motor;

the hydraulic cylinder comprises a cylinder body, a piston and a piston rod, one end of the piston rod is fixedly connected with the piston, the piston is hermetically and slidably connected in the cylinder body, and the piston divides the cylinder body into a first chamber and a second chamber;

the three-position three-way control valve comprises a first oil receiving port, a first hydraulic control oil port, a second oil receiving port, a second hydraulic control oil port and a third oil receiving port;

the first bidirectional constant displacement pump comprises a first oil drain port, a first port and a second port;

the second bidirectional constant displacement pump comprises a second oil drain port, a third port and a fourth port;

the second port and the fourth port are connected in parallel and then connected to the second energy accumulator; the first port, the first oil receiving port and the first hydraulic control oil port are connected in parallel and then communicated with the first chamber; the third port, the second oil receiving port and the second hydraulic control oil port are connected in parallel and then communicated with the second chamber; the third oil receiving port is connected with the first energy accumulator; the first oil drain port is connected between the second port and the fourth port, the second oil drain port is connected between the fourth port and the second energy accumulator,

the first bidirectional constant displacement pump and the second bidirectional constant displacement pump are respectively connected with the driving motor to realize synchronous movement; the driver is communicatively connected to the controller;

each hydraulic module further comprises a first control valve and a second control valve, wherein the first port, the first oil receiving port and the first hydraulic control oil port are connected in parallel and then sequentially connected with the first control valve and the first chamber; the third port, the second oil receiving port and the second hydraulic control oil port are connected in parallel and then sequentially connected with the second control valve and the second chamber; the first control valve and the second control valve are also respectively connected with the controller in a communication way;

the driving motor is a servo motor, and the driver is a servo driver.

2. The motor-driven double-dosing pump double-accumulator distributed direct-drive excavator hydraulic system according to claim 1, wherein: the power supply device is further included, and the driver and the controller are respectively and electrically connected to the power supply device.

3. The motor-driven double-dosing pump double-accumulator distributed direct-drive excavator hydraulic system according to claim 1, wherein: the first control valve and the second control valve are two-position two-way electromagnetic valves respectively.

4. The motor-driven double-dosing pump double-accumulator distributed direct-drive excavator hydraulic system according to claim 1, wherein: the first control valve and the second control valve are two-position two-way cartridge valves respectively.

5. The motor-driven double-dosing pump double-accumulator distributed direct-drive excavator hydraulic system according to claim 1, wherein: each hydraulic module further comprises a first one-way valve, a second one-way valve, a first safety valve and a second safety valve;

the inlet of the first one-way valve and the outlet of the first safety valve are connected in parallel and then connected in parallel with the second port, and the outlet of the first one-way valve and the inlet of the first safety valve are connected in parallel and then connected between the first control valve and the first chamber;

the inlet of the second one-way valve and the outlet of the second safety valve are connected in parallel and then connected to the second accumulator, and the outlet of the second one-way valve and the inlet of the second safety valve are connected in parallel and then connected between the second control valve and the second chamber.

6. The motor-driven double-dosing pump double-accumulator distributed direct-drive excavator hydraulic system according to claim 1 or 2, wherein: the three-position three-way control valve is a three-position three-way hydraulic control valve.

7. The motor-driven double-dosing pump double-accumulator distributed direct-drive excavator hydraulic system according to claim 1 or 2, wherein: the three-position three-way control valve is a three-position three-way cartridge valve.

8. The motor-driven double-dosing pump double-accumulator distributed direct-drive excavator hydraulic system according to claim 1 or 2, wherein: the number of the hydraulic modules is three.