A load-sensitive system, control method and engineering machinery for an electrically driven quantitative pump

Abstract

This invention relates to the field of engineering machinery technology, specifically disclosing an electric-driven fixed displacement pump load-sensitive system, control method, and engineering machinery. The system includes: a control unit, a drive motor assembly, a fixed displacement pump, a pilot hydraulic control unit, a pilot handle assembly, a load-sensitive valve assembly, an actuator assembly, a sensor assembly, and a differential pressure control module. The drive motor drives the fixed displacement pump to supply oil to the load-sensitive valve assembly, thereby driving the actuator assembly. The control unit receives the pump's maximum outlet pressure and maximum load pressure collected by the pressure sensor, and simultaneously receives the system target differential pressure signal from the differential pressure control module, synchronously controlling the motor speed and the target differential pressure output by the proportional pressure reducing valve. This invention aims to solve the problems of traditional pre-valve compensated load-sensitive systems lacking anti-flow saturation functionality, and post-valve compensated load-sensitive systems having additional commutation energy consumption and fixed system differential pressure settings.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to an electric-driven quantitative pump load-sensitive system, control method, and engineering machinery. Background Technology

[0002] In the field of construction machinery, load-sensitive systems are widely used because their pressure compensation characteristics ensure that the handling performance is not affected by the load. However, the electrification and intelligentization of construction machinery have placed higher demands on the energy efficiency and handling performance of load-sensitive systems.

[0003] Existing load-sensitive systems can be divided into pre-valve compensation (LS) systems and post-valve compensation (LUDV) systems. In the pre-valve compensation system, the actuator flow distribution ratio is out of balance when the flow is saturated. In the post-valve compensation system, the main valve core throttling section and the reversing section are separated, resulting in additional reversing throttling losses, which leads to lower energy efficiency than the pre-valve compensation system. Moreover, the pressure difference of both systems is fixed by the pressure regulating spring, which not only causes a large throttling loss at the valve orifice, but also makes it difficult to meet the flow control requirements of different working conditions such as fine adjustment and rapid operation.

[0004] Existing solutions for improving flow saturation in pre-valve compensation systems are either complex or require structural modifications that rely on precise calculations and are susceptible to interference. Variable differential pressure control cannot be applied to pre-valve compensation systems due to structural differences. Traditional constant speed-variable displacement power source methods experience energy efficiency fluctuations under drastic load changes and exhibit mismatches between motor and pump responses. Hybrid control of variable speed-variable displacement also suffers from similar problems, and hydraulic pumps are complex and costly. Therefore, a new system is needed to solve these problems. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an electric-driven quantitative pump load-sensitive system, control method and related engineering machinery, which can effectively solve the problems of existing load-sensitive systems, such as the inability of pre-valve compensation to resist flow saturation, the additional commutation energy consumption of post-valve compensation and the fixed setting of system differential pressure.

[0006] The present invention provides an electric-driven metering pump load-sensitive system, comprising: a control unit, a drive motor assembly, a metering pump, a pilot hydraulic control unit, a pilot handle assembly, a load-sensitive valve assembly, an actuator assembly, a sensor assembly, and a differential pressure control module;

[0007] The output of the control unit is connected to the drive motor assembly and drives the metering pump to operate. The metering pump outputs high-pressure oil to the load-sensitive valve assembly. The load-sensitive valve assembly is configured to regulate the flow rate into the actuator assembly to drive the actuator assembly to operate. The sensor assembly is connected to each valve in the load-sensitive valve assembly and measures its pressure signal. The differential pressure control module obtains the pressure difference signal between the front and rear ends of each valve based on the pressure signal obtained by the sensor assembly. The input of the control unit is connected to the sensor assembly and the differential pressure control module. The control unit regulates the target differential pressure of the valve through the load-sensitive valve assembly based on the pressure signal and the pressure difference signal between the front and rear ends of each valve, thereby controlling the target speed of the drive motor assembly and controlling the control pressure of the pilot hydraulic control unit through the pilot handle assembly.

[0008] Preferably, each valve in the load-sensitive valve assembly includes a differential relief valve, a first pressure compensation valve, a second pressure compensation valve, a first three-position four-way directional valve, a second three-position four-way directional valve, and a shuttle valve. The differential relief valve is located at the oil inlet of the load-sensitive valve assembly, the first pressure compensation valve is located at the oil inlet of the first three-position four-way directional valve, the second pressure compensation valve is located at the oil inlet of the second three-position four-way directional valve, and the shuttle valve is located at the oil outlet of the three-position four-way directional valve. The pilot control terminals of the first three-position four-way directional valve and the second three-position four-way directional valve are connected to the output terminal of the pilot handle assembly.

[0009] Preferably, one end of the valve core of the first pressure compensation valve and the second pressure compensation valve compensates the front-end pressure of the three-position four-way directional valve, and the other end compensates the load pressure and target control pressure at the rear end of the three-position four-way directional valve. The target control pressure oil circuits of the first pressure compensation valve and the second pressure compensation valve are connected in parallel and connected to the output end of the pilot hydraulic control unit.

[0010] Preferably, the first pressure compensation valve and the second pressure compensation valve are configured to maintain the pressure difference between the front and rear ends of the first three-position four-way directional valve and the pressure difference between the front and rear ends of the second three-position four-way directional valve at the target pressure difference of the differential pressure controllable load sensitive valve regulated by the proportional pressure reducing valve in the pilot hydraulic control unit; the first three-position four-way directional valve and the second three-position four-way directional valve are configured to control the operating speed of the actuator assembly by adjusting the valve opening; the differential relief valve is configured to prevent system overpressure; and the shuttle valve is configured to obtain the maximum load pressure of the actuator drive chamber of each branch.

[0011] Preferably, the actuator assembly includes a first actuator and a second actuator, the first actuator being connected to the output port of the first three-position four-way directional valve, and the second actuator being connected to the output port of the second three-position four-way directional valve; the first actuator and the second actuator are hydraulic cylinders or hydraulic motors.

[0012] Preferably, the sensor assembly includes a first pressure sensor and a second pressure sensor. The first pressure sensor is disposed on the load-sensitive valve assembly and configured to detect the maximum load pressure of the system. The second pressure sensor is disposed on the connection pipeline between the metering pump and the load-sensitive valve assembly and configured to detect the outlet pressure of the metering pump.

[0013] Preferably, the pilot handle assembly includes a first pilot handle and a second pilot handle. The input ends of the first pilot handle and the second pilot handle are connected to the pilot hydraulic control unit, and the output ends of the first pilot handle and the second pilot handle are connected to the main valve core opening control end in the load-sensitive valve assembly. The load-sensitive valve assembly is configured to control the target operating speed of the first actuator and the second actuator according to the output signals of the first pilot handle and the second pilot handle, respectively.

[0014] Preferably, the differential pressure control module is configured to provide the system target differential pressure.

[0015] A control method for a load-sensitive system of an electrically driven quantitative pump as described above includes the following steps:

[0016] Step S1: Obtain the system target differential pressure signal set by the differential pressure control module;

[0017] Step S2: Obtain the maximum load pressure signal detected by the first pressure sensor and the pump outlet pressure signal detected by the second pressure sensor in the sensor assembly, and subtract the maximum load pressure from the pump outlet pressure to obtain the actual system pressure difference;

[0018] Step S3: Set the target pressure difference of the valve to the actual pressure difference of the system, control the proportional pressure reducing valve in the pilot hydraulic control unit to output the target pressure difference of the valve to the first pressure compensation valve and the second pressure compensation valve in the load sensitive valve assembly, and then control the pressure difference between the front and rear ends of the first three-position four-way directional valve and the second three-position four-way directional valve to be equal to the current actual pressure difference of the system.

[0019] Step S4: Using the system target pressure difference as the target value and the system actual pressure difference as the feedback value, closed-loop control is performed through the variable speed control of the drive motor. The target speed signal output by the closed-loop controller is sent to the motor controller after being limited, and the motor speed is controlled to maintain the system actual pressure difference stable at the system target pressure difference; return to step S1 to perform the next round of control cycle.

[0020] An engineering machine equipped with an electric-driven quantitative pump load-sensitive system as described above.

[0021] By adopting the above technical solution, the present invention can achieve the following technical effects: The electric-driven quantitative pump load-sensitive system, control method, and related engineering machinery provided by the present invention, during normal system operation, allow the motor speed to change in real time to maintain the actual system pressure difference at the system target pressure difference. When the system enters flow saturation, the motor speed reaches its maximum, the actual system pressure difference decreases, causing the valve target pressure difference to decrease synchronously, resulting in a decrease in flow demand at the current flow area of ​​each throttling orifice. When the total flow demand decreases to equal the pump output flow, the actual system pressure difference and the valve target pressure difference stop decreasing and remain constant, reaching a new equilibrium state. During this process, the pump target pressure difference is equal to the system target pressure difference, and is always greater than the actual system pressure difference; therefore, the motor speed always remains at its maximum value. Furthermore, when the flow area of ​​each main valve core decreases, the actual system pressure difference increases, causing the valve target pressure difference to increase synchronously. When the actual system pressure difference rises to equal the system target pressure difference, the motor speed will show a decreasing trend to maintain the actual system pressure difference at the system target pressure difference. At this point, the system exits the flow saturation state. Therefore, by actively adjusting the target pressure difference of the valve, the system can maintain the flow distribution ratio between light and heavy loads even when the flow is saturated, unaffected by load differences. This achieves the anti-flow saturation function of upstream compensation, effectively avoiding actuator speed misalignment under flow saturation conditions compared to existing upstream compensation load-sensitive systems, resulting in significantly improved control performance. Furthermore, compared to existing downstream compensation load-sensitive systems with anti-flow saturation function, this system can operate under different system pressure differences to obtain variable valve orifice flow gain and avoids the system entering flow saturation. It has a wider effective control stroke, and its fine-tuning and flow control characteristics are significantly improved. Moreover, the system adopts an upstream compensation structure, eliminating additional directional throttling losses and reducing valve orifice throttling losses. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of an electrically driven quantitative pump load-sensitive system provided in the first embodiment of the present invention.

[0024] Figure 2This is a flowchart illustrating a load-sensitive system control method for an electrically driven quantitative pump provided in the second embodiment of the present invention.

[0025] In the diagram: 1-Control unit, 2-Drive motor assembly, 21-Power supply, 22-Motor driver, 23-Drive motor, 3-Metering pump, 4-Pilot hydraulic control unit, 41-Pilot pump, 42-Pilot relief valve, 43-Proportional pressure reducing valve, 5-Pilot handle assembly, 51-First pilot handle, 52-Second pilot handle, 6-Load-sensitive valve assembly, 61-Differential relief valve, 62-First pressure compensation valve, 63-Second pressure compensation valve, 64-First three-position four-way directional valve, 65-Second three-position four-way directional valve, 66-Shuttle valve, 7-Actuator assembly, 71-First actuator, 72-Second actuator, 8-Sensor assembly, 81-First pressure sensor, 82-Second pressure sensor, 9-Differential pressure control module. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention.

[0027] Example

[0028] The following are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the following embodiments. All technical solutions that fall within the scope of the present invention are within the scope of protection of the present invention.

[0029] Reference manual attached Figure 1The first embodiment of the present invention provides an electrically driven quantitative pump load-sensitive system, comprising: a control unit 1, a drive motor assembly 2, a quantitative pump 3, a pilot hydraulic control unit 4, a pilot handle assembly 5, a load-sensitive valve assembly 6, an actuator assembly 7, a sensor assembly 8, and a differential pressure control module 9; wherein, the drive motor assembly 2 drives the quantitative pump 3 to operate, the quantitative pump 3 outputs high-pressure oil to the load-sensitive valve assembly 6, the load-sensitive valve assembly 6 is configured to regulate the flow rate entering the actuator assembly 7 to drive the actuator assembly 7 to operate at a certain speed; the control unit 1 collects signals from the sensor assembly 8 and the differential pressure control module 9, and controls the target speed and differential pressure of the drive motor assembly 2. The pilot hydraulic control unit 4 controls the pressure; the drive motor assembly 2 includes a power supply 21, a motor driver 22, and a drive motor 23. The power supply 21 is electrically connected to the input terminal of the motor driver 22, the output terminal of the motor driver 22 is electrically connected to the drive motor 23, and the output terminal of the drive motor 23 is mechanically connected coaxially to the metering pump 3; the motor driver is configured to receive a target speed signal sent by the control unit and control the drive motor to run at a speed corresponding to the target speed signal; the motor driver 22 is configured to receive a target speed signal sent by the control unit 1 and control the drive motor 23 to run at a speed corresponding to the target speed signal.

[0030] In one possible embodiment of the present invention, the load-sensitive valve assembly 6 is a differential pressure controllable load-sensitive valve assembly, specifically including a differential relief valve 61, a first pressure compensation valve 62, a second pressure compensation valve 63, a first three-position four-way directional valve 64, a second three-position four-way directional valve 65, and a shuttle valve 66. The differential relief valve 61 is disposed at the oil inlet of the load-sensitive valve assembly 6, the first pressure compensation valve 62 is disposed at the oil inlet of the first three-position four-way directional valve 64, the second pressure compensation valve 63 is disposed at the oil inlet of the second three-position four-way directional valve 65, and the shuttle valve 66 is disposed at the oil outlets of the first three-position four-way directional valve 64 and the second three-position four-way directional valve 65. The input ends of the first three-position four-way directional valve 64 and the second three-position four-way directional valve 65 are connected to the output end of the pilot handle assembly 5. One end of the valve core of the first pressure compensation valve 62 and the second pressure compensation valve 63 respectively acts on the first three-position four-way directional valve 64 and the second three-position four-way directional valve 65. The pressure at the front end of the four-way directional valve 65 is used to control the load pressure and target control pressure at the rear ends of the first three-way four-way directional valve 64 and the second three-way four-way directional valve 65, respectively. The target control pressure oil circuits of the first pressure compensation valve 62 and the second pressure compensation valve 63 are connected in parallel and connected to the valve target pressure difference output by the pilot hydraulic control unit 4. The first pressure compensation valve 62 and the second pressure compensation valve 63 are configured to maintain the pressure difference between the front and rear ends of the first three-way four-way directional valve 64 and the pressure difference between the front and rear ends of the second three-way four-way directional valve 65 at the valve target pressure difference of the pressure difference controllable load sensitive valve regulated by the proportional pressure reducing valve 43 in the pilot hydraulic control unit 4, respectively. The first three-way four-way directional valve 64 and the second three-way four-way directional valve 65 are configured to control the operating speed of the actuator assembly 7 by adjusting the valve opening. The differential relief valve 61 is configured to prevent system overpressure. The shuttle valve 66 is configured to obtain the maximum load pressure of the actuator drive chamber of each branch.

[0031] In one possible embodiment of the present invention, the pilot hydraulic control unit 4 includes a pilot pump 41, a pilot relief valve 42, and a proportional pressure reducing valve 43. The pilot relief valve 42 is arranged at the outlet of the pilot pump 41 to set a primary pilot pressure. The primary pilot pressure is supplied to the input ends of the proportional pressure reducing valve 43 and the pilot handle assembly 5, respectively. The input end of the proportional pressure reducing valve 43 is connected to the output end of the control unit 1 to realize the real-time adjustment of the valve target differential pressure according to the actual differential pressure of the system. The output end of the proportional pressure reducing valve 43 is connected to the load-sensitive valve assembly 6 to realize the setting pressure of the valve target differential pressure for the load-sensitive valve assembly 6.

[0032] In one possible embodiment of the present invention, the actuator assembly 7 includes a first actuator 71 and a second actuator 72, wherein the first actuator 71 is connected to the output port of the first three-position four-way directional valve 64, and the second actuator 72 is connected to the output port of the second three-position four-way directional valve 65; the first actuator 71 and the second actuator 72 are hydraulic cylinders or hydraulic motors.

[0033] In one possible embodiment of the present invention, the sensor assembly 8 includes a first pressure sensor 81 and a second pressure sensor 82. The first pressure sensor 81 is disposed on the load-sensitive valve assembly 6 and is configured to detect the maximum load pressure of the system. The second pressure sensor 82 is disposed on the connecting pipeline between the metering pump 3 and the load-sensitive valve assembly 6 and is configured to detect the outlet pressure of the metering pump 3.

[0034] In one possible embodiment of the present invention, the pilot handle assembly 5 includes a first pilot handle 51 and a second pilot handle 52. The input ends of the first pilot handle 51 and the second pilot handle 52 are connected to the pilot hydraulic control unit 4, and the output ends of the first pilot handle 51 and the second pilot handle 52 are connected to the main valve core opening control end in the load-sensitive valve assembly 6. The load-sensitive valve assembly 6 is configured to control the target operating speeds of the first actuator 71 and the second actuator 72 according to the output signals of the first pilot handle 51 and the second pilot handle 52, respectively. The differential pressure control module 9 is configured to provide the system target differential pressure.

[0035] In this embodiment, during normal operation, the motor speed changes in real time to maintain the actual system pressure difference at the system target pressure difference. When the system reaches flow saturation, the motor speed reaches its maximum, and the actual system pressure difference decreases, causing the valve target pressure difference to decrease synchronously, resulting in a decrease in flow demand at the current flow area of ​​each throttling orifice. When the total flow demand drops to equal the pump output flow, the actual system pressure difference and the valve target pressure difference stop decreasing and remain constant, reaching a new equilibrium state. During this process, the pump target pressure difference is equal to the system target pressure difference and is always greater than the actual system pressure difference; therefore, the motor speed always remains at its maximum value. Furthermore, when the flow area of ​​each main valve core decreases, the actual system pressure difference increases, causing the valve target pressure difference to increase synchronously. When the actual system pressure difference rises to equal the system target pressure difference, the motor speed will show a decreasing trend to maintain the actual system pressure difference at the system target pressure difference. At this point, the system exits the flow saturation state. Therefore, by actively adjusting the target pressure difference of the valve, the system can maintain the flow distribution ratio between light and heavy loads even when the flow is saturated, unaffected by load differences. This achieves the anti-flow saturation function of upstream compensation, effectively avoiding actuator speed misalignment under flow saturation conditions compared to existing upstream compensation load-sensitive systems, resulting in significantly improved control performance. Furthermore, compared to existing downstream compensation load-sensitive systems with anti-flow saturation function, this system can operate under different system pressure differences to obtain variable valve orifice flow gain and avoids the system entering flow saturation. It has a wider effective control stroke, and its fine-tuning and flow control characteristics are significantly improved. Moreover, the system adopts an upstream compensation structure, eliminating additional directional throttling losses and reducing valve orifice throttling losses.

[0036] Reference manual attached Figure 2 The second embodiment of the present invention provides a control method for a load-sensitive system of an electrically driven quantitative pump, comprising the following steps:

[0037] Step S1: Obtain the system target differential pressure signal set by the differential pressure control module;

[0038] Step S2: Obtain the maximum load pressure signal detected by the first pressure sensor and the pump outlet pressure signal detected by the second pressure sensor in the sensor assembly, and subtract the maximum load pressure from the pump outlet pressure to obtain the actual system pressure difference;

[0039] Step S3: Set the target pressure difference of the valve to the actual pressure difference of the system, control the proportional pressure reducing valve in the pilot hydraulic control unit to output the target pressure difference of the valve to the first pressure compensation valve and the second pressure compensation valve in the load sensitive valve assembly, and then control the pressure difference between the front and rear ends of the first three-position four-way directional valve and the second three-position four-way directional valve to be equal to the current actual pressure difference of the system.

[0040] Step S4: Using the system target pressure difference as the target value and the system actual pressure difference as the feedback value, closed-loop control is performed through the variable speed control of the drive motor. The target speed signal output by the closed-loop controller is sent to the motor controller after being limited (limiting the maximum speed and the minimum speed) to control the motor speed to maintain the system actual pressure difference stable at the system target pressure difference; return to step S1 to perform the next round of control cycle.

[0041] The third embodiment of the present invention also provides an engineering machine equipped with the electric-driven quantitative pump load-sensing system described above.

[0042] The engineering machinery mentioned can be, for example, a series of large-scale engineering machinery equipment such as excavators and earthmoving machines.

[0043] This invention employs a load-sensitive valve assembly (including a three-position four-way directional valve and a pressure compensation valve located at the oil inlet, which is a pre-valve compensation), paired with a pilot handle assembly and a differential pressure control module. The valve group is indirectly controlled through hydraulic control signals, and the differential pressure control module directly sets the system target differential pressure. The valve target differential pressure is set as the actual differential pressure detected by the sensor. Then, the actual differential pressure is stabilized at the target differential pressure through motor variable speed closed-loop control. This invention addresses the problems of pre-valve compensation resisting flow saturation difference, post-valve compensation having additional directional energy consumption, and the narrow flow control range caused by fixed differential pressure.

[0044] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A load-sensitive system for an electrically driven quantitative pump, characterized in that, include: Control unit, drive motor assembly, metering pump, pilot hydraulic control unit, pilot handle assembly, load-sensitive valve assembly, actuator assembly, sensor assembly, and differential pressure control module; The output of the control unit is connected to the drive motor assembly and drives the metering pump. The metering pump outputs high-pressure oil to the load-sensitive valve assembly. The load-sensitive valve assembly is configured to regulate the flow rate into the actuator assembly to drive the actuator assembly. The sensor assembly is connected to each valve in the load-sensitive valve assembly and measures its pressure signal. The differential pressure control module calculates the pressure difference signal between the front and rear ends of each valve based on the pressure signal obtained by the sensor assembly. The input of the control unit is connected to the sensor assembly and the differential pressure control module. The control unit regulates the target differential pressure of the valve through the load-sensitive valve assembly based on the pressure signal and the pressure difference signal between the front and rear ends of each valve, thereby controlling the target speed of the drive motor assembly and controlling the control pressure of the pilot hydraulic control unit through the pilot handle assembly. Each valve in the load-sensitive valve assembly includes a differential relief valve, a first pressure compensation valve, a second pressure compensation valve, a first three-position four-way directional valve, a second three-position four-way directional valve, and a shuttle valve. The differential relief valve is configured in the load-sensitive valve assembly. At the oil inlet, the first pressure compensation valve is configured at the oil inlet of the first three-position four-way directional valve, the second pressure compensation valve is configured at the oil inlet of the second three-position four-way directional valve, and the shuttle valve is configured at the oil outlet of the three-position four-way directional valve; one end of the valve core of the first pressure compensation valve and the second pressure compensation valve compensates the front-end pressure of the first three-position four-way directional valve and the second three-position four-way directional valve, and the other end compensates the load pressure and target control pressure of the rear end of the first three-position four-way directional valve and the second three-position four-way directional valve; the first pressure compensation valve and the second pressure compensation valve are configured to maintain the pressure difference between the front and rear ends of the first three-position four-way directional valve and the pressure difference between the front and rear ends of the second three-position four-way directional valve at the valve target pressure difference of the differential pressure controllable load sensitive valve regulated by the proportional pressure reducing valve in the pilot hydraulic control unit; the first three-position four-way directional valve and the second three-position four-way directional valve are configured to control the operating speed of the actuator assembly by adjusting the valve opening; the differential relief valve is configured to prevent system overpressure; and the shuttle valve is configured to obtain the maximum load pressure of the actuator drive chamber of each branch.

2. The load-sensitive system for an electrically driven metering pump according to claim 1, characterized in that, The pilot control terminals of the first three-position four-way directional valve and the second three-position four-way directional valve are connected to the output terminal of the pilot handle assembly.

3. The load-sensitive system for an electrically driven quantitative pump according to claim 2, characterized in that, The target control pressure oil circuits of the first pressure compensation valve and the second pressure compensation valve are connected in parallel and connected to the output terminal of the pilot hydraulic control unit.

4. The load-sensitive system for an electrically driven quantitative pump according to claim 2, characterized in that, The actuator assembly includes a first actuator and a second actuator. The first actuator is connected to the output port of the first three-position four-way directional valve, and the second actuator is connected to the output port of the second three-position four-way directional valve. The first actuator and the second actuator are hydraulic cylinders or hydraulic motors.

5. The load-sensitive system for an electrically driven quantitative pump according to claim 1, characterized in that, The sensor assembly includes a first pressure sensor and a second pressure sensor. The first pressure sensor is disposed on the load-sensitive valve assembly and configured to detect the maximum load pressure of the system. The second pressure sensor is disposed on the connecting pipeline between the metering pump and the load-sensitive valve assembly and configured to detect the outlet pressure of the metering pump.

6. The load-sensitive system for an electrically driven quantitative pump according to claim 4, characterized in that, The pilot handle assembly includes a first pilot handle and a second pilot handle. The input ends of the first pilot handle and the second pilot handle are connected to the pilot hydraulic control unit, and the output ends of the first pilot handle and the second pilot handle are connected to the main valve core opening control end in the load-sensitive valve assembly. The load-sensitive valve assembly is configured to control the target operating speed of the first actuator and the second actuator according to the output signals of the first pilot handle and the second pilot handle, respectively.

7. The load-sensitive system for an electrically driven quantitative pump according to claim 1, characterized in that, The differential pressure control module is configured to provide the system target differential pressure.

8. A control method for a load-sensitive system of an electrically driven quantitative pump as described in any one of claims 1-7, characterized in that, Includes the following steps: Step S1: Obtain the system target differential pressure signal set by the differential pressure control module; Step S2: Obtain the maximum load pressure signal detected by the first pressure sensor and the pump outlet pressure signal detected by the second pressure sensor in the sensor assembly, and subtract the maximum load pressure from the pump outlet pressure to obtain the actual system pressure difference; Step S3: Set the target pressure difference of the valve to the actual pressure difference of the system, control the proportional pressure reducing valve in the pilot hydraulic control unit to output the target pressure difference of the valve to the first pressure compensation valve and the second pressure compensation valve in the load sensitive valve assembly, and then control the pressure difference between the front and rear ends of the first three-position four-way directional valve and the second three-position four-way directional valve to be equal to the current actual pressure difference of the system. Step S4: Using the system target pressure difference as the target value and the system actual pressure difference as the feedback value, closed-loop control is performed through the variable speed control of the drive motor. The target speed signal output by the closed-loop controller is sent to the motor controller after being limited, so as to control the motor speed to maintain the system actual pressure difference stable at the system target pressure difference. Return to step S1 and proceed to the next control loop.

9. An engineering machinery, characterized in that, It is equipped with an electric-driven metering pump load-sensitive system as described in any one of claims 1-7.

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