A hydraulic pump control system, control method, and engineering machinery equipment

Abstract

This invention relates to the field of engineering machinery technology, and discloses a hydraulic pump control system, control method, and engineering machinery equipment. The system includes: a hydraulic oil supply unit for drawing hydraulic oil from a main hydraulic oil tank, or a main hydraulic oil tank and an auxiliary hydraulic oil tank, to provide working oil to the actuator; a hydraulic oil return control unit for adjusting the direction of the return oil from the actuator, so that the return oil flows to the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank; an anti-vacuum control unit for controlling the entry of hydraulic oil from the auxiliary hydraulic oil tank into the hydraulic oil supply unit; and a control unit for controlling the working status of the hydraulic oil return control unit and the anti-vacuum control unit. This invention can control the hydraulic oil from the auxiliary hydraulic oil pump to participate in the circulation of the hydraulic system according to the working status of the hydraulic pump, realizing intelligent control of the hydraulic pump's oil intake based on the physical structure, ensuring the stable operation of the hydraulic pump under various working conditions, and protecting the hydraulic pump.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to a hydraulic pump control system, control method, and engineering machinery equipment. Background Technology

[0002] During earthmoving or mining operations, various working conditions, such as temperature changes or steep road slopes, can cause hydraulic pumps to experience cavitation. Taking mining excavators as an example, in large-scale mining operations, frequent ascents and descents of steep slopes, especially during rapid movements, coupled with the extremely harsh mining environment and high hydraulic oil viscosity at low temperatures, can lead to poor oil suction or cavitation in the hydraulic pumps. This can range from minor pump cavitation to severe piston wear and eventual failure, contaminating the entire hydraulic system, causing significant delays in the project, and incurring high maintenance costs.

[0003] In existing technologies, the main solutions to prevent hydraulic pump cavitation are to reduce the height difference between the hydraulic pump and the hydraulic oil tank and to design pressure compensation methods in the hydraulic oil pipeline. However, due to space limitations in the design of engineering machinery, not all of these solutions are applicable. Furthermore, adding pressure compensation methods to the hydraulic oil can lead to large pressure fluctuations, which greatly affects the comfort of operation. Summary of the Invention

[0004] In view of this, the present invention provides a hydraulic pump control system, control method and engineering machinery equipment to solve the problem of not being able to smoothly achieve anti-cavitation.

[0005] In a first aspect, the present invention provides a hydraulic pump control system, comprising: a control unit, a hydraulic oil supply unit, an execution unit, a hydraulic oil return control unit, a main hydraulic oil tank, an auxiliary hydraulic oil tank, and an anti-vacuum control unit; the hydraulic oil supply unit has its input end connected to the main hydraulic oil tank and the auxiliary hydraulic oil tank, and its output end connected to the first end of the execution unit, for drawing hydraulic oil from the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank, to provide working oil to the execution unit; the hydraulic oil return control unit is connected to the second end of the execution unit, for adjusting the direction of the return oil from the execution unit, so that the return oil flows to the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank; the anti-vacuum control unit is connected to the output end of the hydraulic oil supply unit, for controlling the hydraulic oil from the auxiliary hydraulic oil tank to enter the hydraulic oil supply unit; the control unit is connected to the hydraulic oil return control unit and the anti-vacuum control unit, for controlling the working state of the hydraulic oil return control unit and the anti-vacuum control unit.

[0006] The hydraulic pump control system provided by this invention controls the working states of the hydraulic oil return control unit and the anti-vacuum control unit through a control unit. The anti-vacuum control unit controls the flow of hydraulic oil from the auxiliary hydraulic oil tank into the hydraulic oil supply unit. The hydraulic oil return control unit adjusts the direction of the return oil from the actuator, causing the return oil to enter the main hydraulic oil tank, or both the main and auxiliary hydraulic oil tanks. This allows the hydraulic oil supply unit to draw hydraulic oil from the main hydraulic oil tank, or both, to supply working oil to the actuator. By deploying the anti-vacuum control unit, this invention can control the hydraulic oil from the auxiliary hydraulic oil pump to participate in the hydraulic system circulation according to the working state of the hydraulic pump. Based on the physical structure, it achieves intelligent control of the hydraulic pump's oil intake, ensuring stable operation of the hydraulic pump under various working conditions, protecting the hydraulic pump, and thus ensuring the normal progress of engineering operations.

[0007] In one optional embodiment, the hydraulic oil supply unit includes: a power unit, a piston hydraulic main pump, and a pilot gear pump; the power unit is connected to the drive end of the piston hydraulic main pump and the drive end of the pilot gear pump, and is used to provide hydraulic energy to the piston hydraulic main pump and the pilot gear pump; the piston hydraulic main pump has its input end connected to the main hydraulic oil tank and the auxiliary hydraulic oil tank, and its output end connected to the actuator, and is used to draw hydraulic oil from the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank, to provide working oil to the actuator; the pilot gear pump has its input end connected to the main hydraulic oil tank and the auxiliary hydraulic oil tank, and its output end connected to the anti-vacuum control unit, and is used to draw hydraulic oil from the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank, to provide pilot control oil to the anti-vacuum control unit.

[0008] In this embodiment of the invention, a power unit and a plunger hydraulic main pump provide a working oil source to the actuator, enabling the actuator to operate normally under the action of the working oil. Simultaneously, a pilot gear pump provides pilot control oil to the anti-vacuum control unit, thereby opening the control valve under the pressure of the pilot control oil. This connects the return and suction lines corresponding to the auxiliary hydraulic oil tank, allowing the hydraulic oil in the auxiliary hydraulic oil tank to participate in the hydraulic circulation.

[0009] In one optional embodiment, the hydraulic oil return control unit includes: a back pressure valve and a bypass valve. The back pressure valve has a first end connected to the execution unit and a second end connected to the main hydraulic oil tank, and is used to open when the current pressure of the back pressure valve reaches a first preset pressure, so that the return oil flows to the main hydraulic oil tank. The bypass valve has a first end connected to the execution unit and a second end connected to the main hydraulic oil tank and the auxiliary hydraulic oil tank, and is used to open when the current pressure of the back pressure valve reaches a second preset pressure, so that the return oil flows to the main hydraulic oil tank and the auxiliary hydraulic oil tank.

[0010] This invention deploys a back pressure valve and a bypass valve in the hydraulic oil return control unit, which can control the valve opening based on the return oil pressure. When the return oil volume is small, only the back pressure valve is opened, and when the return oil volume is large, the bypass valve is added to improve the flow capacity and ensure that all the return oil is discharged into the hydraulic oil tank, thus avoiding situations such as cavitation caused by hydraulic circuit blockage.

[0011] In an optional embodiment, the system further includes: a first control valve and a second control valve. The anti-vacuum control unit includes: a proportional control solenoid valve; the first control valve, with a first end connected to the input end of the auxiliary hydraulic oil tank and a second end connected to the second end of a bypass valve, for adjusting the hydraulic oil input of the auxiliary hydraulic oil tank; the second control valve, with a first end connected to the output end of the auxiliary hydraulic oil tank and a second end connected to the piston hydraulic main pump and the pilot gear pump, for adjusting the hydraulic oil output of the auxiliary hydraulic oil tank; and the proportional control solenoid valve, with a control end connected to the control unit, an input end connected to the pilot gear pump, and an output end connected to the drive end of the first control valve and the drive end of the second control valve, for opening under the control command generated by the control unit based on the oil suction status of the hydraulic oil supply unit, and outputting pilot control oil to the first control valve and the second control valve so that the first control valve and the second control valve open synchronously.

[0012] This invention, by deploying a proportional control solenoid valve, can synchronously control the opening of the control valves at both ends of the auxiliary hydraulic oil tank by adjusting the opening degree of the proportional control solenoid valve. Based on the physical structure, this allows the hydraulic oil in the auxiliary hydraulic oil tank to enter the hydraulic circulation, and achieves point-to-point compensation when the hydraulic pump is insufficient to draw oil. This helps to maintain a constant system pressure, avoid pressure fluctuations that affect the operating performance, and thus improve the energy utilization efficiency of the hydraulic oil and avoid engine power loss.

[0013] In one optional embodiment, the system further includes: an oil level sensor and a suction pressure sensor; the oil level sensor is deployed in the auxiliary hydraulic oil tank to detect the oil level in the auxiliary hydraulic oil tank; the suction pressure sensor is deployed in the piston hydraulic main pump and the suction line between the main hydraulic oil tank and the auxiliary hydraulic oil tank to detect the suction pressure in the suction line.

[0014] This invention, by deploying an oil level sensor and an oil suction pressure sensor, can accurately measure the oil suction status of the hydraulic pump, and then adjust the continuity of the hydraulic circulation pipeline according to the oil suction status to avoid the occurrence of hydraulic pump cavitation.

[0015] Secondly, the present invention provides a hydraulic pump control method. The hydraulic pump control system includes a control unit, a hydraulic oil supply unit, an execution unit, a hydraulic oil return control unit, a main hydraulic oil tank, an auxiliary hydraulic oil tank, and an anti-vacuum control unit. The control method is applied to the control unit and includes: acquiring the hydraulic oil demand of the execution unit; controlling the hydraulic oil supply unit to draw in hydraulic oil according to the hydraulic oil demand to provide working oil to the execution unit; controlling the working state of the hydraulic oil return control unit according to the return oil status of the execution unit so that the return oil from the execution unit flows to the main hydraulic oil tank or the main hydraulic oil tank and the auxiliary hydraulic oil tank; and controlling the working state of the anti-vacuum control unit according to the suction status of the hydraulic oil supply unit so that the hydraulic oil from the main hydraulic oil tank or the main hydraulic oil tank and the auxiliary hydraulic oil tank enters the hydraulic oil supply unit.

[0016] The hydraulic pump control method provided by this invention controls the working state of the hydraulic oil return control unit and the anti-vacuum control unit based on the return oil status and suction oil status. This ensures that the return oil from the actuator enters the main hydraulic oil tank, or both the main and auxiliary hydraulic oil tanks, allowing the hydraulic oil supply unit to draw hydraulic oil from the main hydraulic oil tank, or both, to supply working oil to the actuator. By deploying the anti-vacuum control unit and adjusting the control logic, this invention can control the hydraulic oil from the auxiliary hydraulic oil pump to participate in the hydraulic system circulation according to the working state of the hydraulic pump. Based on the physical structure, it achieves intelligent control of the hydraulic pump's oil suction, ensuring stable operation of the hydraulic pump under various working conditions, protecting the hydraulic pump, and thus ensuring the normal progress of engineering operations.

[0017] In one optional embodiment, the hydraulic oil return control unit includes a back pressure valve and a bypass valve. Controlling the operating state of the hydraulic oil return control unit according to the return oil status of the actuator, so that the return oil from the actuator flows to the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank, includes: acquiring the current pressure of the back pressure valve and determining whether the current pressure is higher than a first preset pressure or a second preset pressure, wherein the first preset pressure is lower than the second preset pressure; if the current pressure is higher than the first preset pressure, controlling the back pressure valve to open so that the return oil flows to the main hydraulic oil tank; if the current pressure is higher than the second preset pressure, controlling the bypass valve to open when the back pressure valve is open so that the return oil flows to the main hydraulic oil tank and the auxiliary hydraulic oil tank.

[0018] This invention controls the opening and closing of the back pressure valve and bypass valve in the hydraulic oil return control unit. By adding a bypass valve, the return oil flow can be increased, and the return oil direction can be adjusted according to the actual return oil conditions. Thus, under conditions of high flow and high hydraulic pump suction demand, all the return oil from the actuator is discharged into the hydraulic oil tank, initially preventing the hydraulic pump from sucking in air.

[0019] In one optional embodiment, the hydraulic pump control system further includes: a first control valve and a second control valve; the anti-vacuum control unit includes: a proportional control solenoid valve; and a suction pressure sensor is deployed on the suction pipeline between the hydraulic oil supply unit and the main hydraulic oil tank and the auxiliary hydraulic oil tank. The anti-vacuum control unit's operating state is controlled according to the suction status of the hydraulic oil supply unit to allow hydraulic oil from the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank, to enter the hydraulic oil supply unit. This includes: acquiring the suction pressure of the suction pipeline and determining whether the suction pressure is lower than a third preset pressure or a fourth preset pressure, wherein the third preset pressure is greater than the fourth preset pressure; if the suction pressure is not lower than the third preset pressure, then the control unit is activated. The proportional control solenoid valve is closed to allow hydraulic oil from the main hydraulic tank to enter the hydraulic oil supply unit. If the suction pressure is lower than the third preset pressure, the proportional control solenoid valve is opened according to the suction pressure to simultaneously open the first and second control valves. The return oil enters the auxiliary hydraulic tank at a preset flow rate, and the hydraulic oil in the auxiliary hydraulic tank enters the hydraulic oil supply unit at a preset flow rate. If the suction pressure is lower than the fourth preset pressure, the proportional control solenoid valve is opened to its maximum opening to simultaneously open the first and second control valves to their maximum opening. The return oil enters the auxiliary hydraulic tank at its maximum flow rate, and the hydraulic oil in the auxiliary hydraulic tank enters the hydraulic oil supply unit at its maximum flow rate.

[0020] This invention controls the opening and closing of the proportional control solenoid valve in the anti-cavitation control unit according to the oil suction pressure. Based on the action of the pilot control oil, it can open the input and output ends of the auxiliary hydraulic oil tank, so that the hydraulic oil of the auxiliary hydraulic oil pump participates in the circulation of the hydraulic system, further preventing the occurrence of hydraulic pump cavitation.

[0021] In one optional embodiment, the auxiliary hydraulic oil tank is equipped with an oil level sensor. During the process of controlling the operation of the anti-vacuum control unit based on the oil suction status of the hydraulic oil supply unit to allow hydraulic oil from the main hydraulic oil tank, or both the main and auxiliary hydraulic oil tanks, to enter the hydraulic oil supply unit, the method further includes: acquiring the real-time oil level of the auxiliary hydraulic oil tank and determining whether the real-time oil level has changed; if it has changed, generating a first alarm signal; determining whether the suction pressure is lower than a fifth preset pressure; if the fifth preset pressure is lower than a fourth preset pressure, adjusting the control strategy and generating a second alarm signal.

[0022] This invention, by detecting the oil level in the auxiliary hydraulic oil tank, accurately reflects the stability of the hydraulic pump's oil suction and return, enabling point-to-point compensation when the hydraulic pump's oil suction is insufficient. This helps maintain constant system pressure and avoids pressure fluctuations that could affect operational performance. Simultaneously, an alarm is triggered when the oil suction pressure is too low, promptly alerting the operator when the hydraulic pump experiences cavitation and preventing damage to the hydraulic system.

[0023] Thirdly, the present invention provides an engineering machinery equipment, including the hydraulic pump control system of the first aspect or any corresponding embodiment described above.

[0024] Since engineering machinery equipment includes a hydraulic pump control system, which has the same effect as the hydraulic pump control system, it will not be elaborated here. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a structural block diagram of a hydraulic pump control system according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic flowchart of a hydraulic pump control method according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic flowchart of another hydraulic pump control method according to an embodiment of the present invention.

[0029] Figure Descriptions: 100-Hydraulic oil supply unit; 101-Power unit; 102-Piston hydraulic main pump; 103-Gear pump; 200-Actuation unit; 201-Control device; 202-Actuator; 300-Hydraulic oil return control unit; 301-Back pressure valve; 302-Bypass valve; 303-First throttle valve; 304-Second throttle valve; 400-Main hydraulic oil tank; 401-Dip gauge; 402-First return oil filter; 403-First suction oil filter; 500-Auxiliary hydraulic oil tank; 501-Oil level sensor; 502-Second return oil filter; 503-Second suction oil filter; 600-Anti-vacuum control unit; 601-Solenoid valve; 701-First control valve; 702-Second control valve; 801-Suction pressure sensor; 802-Working pressure sensor; 900-Hydraulic oil cooling unit. Detailed Implementation

[0030] 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 some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] This invention is applicable to scenarios where hydraulic oil circulation in a hydraulic system is adjusted according to the operating conditions of construction machinery to prevent hydraulic oil from cavitating. Taking a mining excavator as an example, the hydraulic system of an excavator typically uses a constant power control method to ensure its efficient and stable operation. Constant power control follows the basic formula "power = pressure × flow rate," ensuring that the system maintains constant power under different load conditions by adjusting the output flow rate of the hydraulic pump in real time, thereby achieving a balance between energy saving and performance. However, this control method carries the risk of hydraulic pump cavitation when facing drastic load changes. For example, when the excavator is digging, the hydraulic system needs to overcome the resistance of materials such as soil and rocks, at which point the load is extremely high (pressure increases). According to the constant power control principle, to ensure constant power, the hydraulic pump will automatically reduce the output flow rate. As the output flow rate decreases, the return oil flow rate of the hydraulic system also decreases, and the entire system operates in a high-pressure, low-flow state. When the excavation operation is completed and the load decreases instantaneously—for example, when the bucket is pulled out of the soil or material is quickly unloaded—the actuators (such as hydraulic cylinders and hydraulic motors) need to quickly complete actions such as resetting and rotation. This requires the hydraulic pump to supply a large amount of hydraulic oil in a short time to achieve high-speed operation. The hydraulic pump will immediately increase its output flow rate, and the return flow rate will also increase instantaneously. However, the hydraulic pump's suction capacity has an upper limit. When the system's flow demand increases sharply, exceeding the hydraulic pump's maximum suction capacity, a cavitation problem will occur.

[0032] Hydraulic pump cavitation essentially refers to the situation where, during the oil suction process, air mixes into the hydraulic oil because the pressure inside the suction chamber is lower than atmospheric pressure. When the load decreases instantaneously and the hydraulic pump's output flow increases sharply, if the suction port cannot replenish enough hydraulic oil in time, the pressure inside the suction chamber drops rapidly. Once the pressure drops to a certain level, below the air separation pressure, the air originally dissolved in the hydraulic oil will precipitate out, forming bubbles. If the pressure drops further below atmospheric pressure, outside air can also enter the system through sealing gaps in the suction pipe. These bubbles enter the hydraulic pump with the hydraulic oil. When they enter the high-pressure area, the bubbles will rapidly burst, generating localized high temperatures and high-pressure impacts. This not only causes vibration and noise but also causes cavitation damage to the internal components of the hydraulic pump, severely affecting the service life of the hydraulic pump and the stable operation of the system.

[0033] In this situation, the relevant technology mainly utilizes the main pressure of the hydraulic pump for oil suction compensation. This includes the hydraulic pump, cartridge valve, and switching valve. The hydraulic pump's suction port is connected to the oil tank. The switching valve is controlled based on the suction port pressure, thereby connecting the cartridge valve and the oil tank. Under the pressure difference between the outlet and the oil tank, the cartridge valve can actuate, connecting the suction port and the outlet. At this time, the hydraulic oil at the outlet can replenish the suction port. However, the above process can cause sudden fluctuations in the hydraulic pump's working flow and pressure, affecting the operation of the entire excavator. Furthermore, if the main pressure of the hydraulic pump is too high, even with pressure valves and throttle valves, precise and efficient oil suction pressure compensation cannot be achieved. Moreover, it cannot protect the hydraulic pump; excessively high suction pressure can damage the seals in the hydraulic pump's suction plate area or cause pipe bursts. It also cannot accurately control the required hydraulic oil flow caused by cavitation in the hydraulic pump, resulting in wasted hydraulic oil energy and reduced engine power. Therefore, this embodiment of the invention provides a hydraulic pump control method, which deploys a main hydraulic oil tank and an auxiliary hydraulic oil tank, and adjusts the hydraulic circulation direction according to the return oil condition and the suction oil condition, so that the hydraulic oil in the auxiliary hydraulic oil tank can participate in the hydraulic circulation in a timely manner, thereby preventing the hydraulic pump from sucking in air.

[0034] According to embodiments of the present invention, a hydraulic pump control system embodiment is provided. It should be noted that, as used below, the term "module" can refer to a combination of software and / or hardware that implements a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0035] This embodiment provides a hydraulic pump control system, such as Figure 1 The structural block diagram shown illustrates that the system includes: a control unit, a hydraulic oil supply unit 100, an execution unit 200, a hydraulic oil return control unit 300, a main hydraulic oil tank 400, an auxiliary hydraulic oil tank 500, and an anti-vacuum control unit 600. The hydraulic oil supply unit 100 has its input end connected to the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500, and its output end connected to the first end of the execution unit 200. It is used to draw hydraulic oil from the main hydraulic oil tank 400, or the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500, to provide working oil to the execution unit 200. The hydraulic oil return control unit... Unit 300, connected to the second end of execution unit 200, is used to adjust the direction of return oil from execution unit 200, so that the return oil flows to main hydraulic oil tank 400, or main hydraulic oil tank 400 and auxiliary hydraulic oil tank 500; anti-vacuum control unit 600, connected to the output end of hydraulic oil supply unit 100, is used to control the hydraulic oil from auxiliary hydraulic oil tank 500 to enter hydraulic oil supply unit 100; control unit, connected to hydraulic oil return control unit 300 and anti-vacuum control unit 600, is used to control the working status of hydraulic oil return control unit and anti-vacuum control unit.

[0036] Specifically, in embodiments of the present invention, such as Figure 1 As shown, the hydraulic oil supply unit 100 includes: a power unit 101, a piston hydraulic main pump 102, and a pilot gear pump 103; the power unit 101 is connected to the drive end of the piston hydraulic main pump 102 and the drive end of the pilot gear pump 103, and is used to provide hydraulic energy to the piston hydraulic main pump 102 and the pilot gear pump 103; the piston hydraulic main pump 102 has its input end connected to the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500, and its output end connected to the execution unit 200. The pilot gear pump 103 is used to draw hydraulic oil from the main hydraulic oil tank 400, or the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500, to provide working oil for the actuator 200; the pilot gear pump 103 has its input end connected to the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500, and its output end connected to the anti-vacuum control unit 600, and is used to draw hydraulic oil from the main hydraulic oil tank 400, or the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500, to provide pilot control oil for the anti-vacuum control unit 600.

[0037] In some alternative implementations, such as Figure 1 As shown, the hydraulic oil return control unit 300 includes: a back pressure valve 301, a bypass valve 302, a first throttle valve 303, and a second throttle valve 304. The back pressure valve 301 has a first end connected to the execution unit 200 and a second end connected to the main hydraulic oil tank 400. It is used to open when the current pressure of the back pressure valve 301 reaches a first preset pressure, so that the return oil flows to the main hydraulic oil tank 400. The bypass valve 302 has a first end connected to the execution unit 200 and a second end connected to the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500. It is used to open when the current pressure of the back pressure valve 301 reaches a second preset pressure, so that the return oil flows to the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500.

[0038] In some alternative implementations, such as Figure 1As shown, the system also includes: a first control valve 701 and a second control valve 702. The anti-vacuum control unit 600 includes: a proportional control solenoid valve 601; the first control valve 701, with its first end connected to the input end of the auxiliary hydraulic oil tank 500 and its second end connected to the second end of the bypass valve 302, is used to adjust the hydraulic oil input of the auxiliary hydraulic oil tank 500, that is, to control the flow rate between the hydraulic oil return control unit 300 and the auxiliary hydraulic oil tank 500, and the size of the flow passage is controlled by the pressure provided by the proportional control solenoid valve 601; the second control valve 702, with its first end connected to the output end of the auxiliary hydraulic oil tank 500 and its second end connected to the plunger hydraulic main pump 102 and the pilot gear pump 103. The hydraulic oil output of the auxiliary hydraulic oil tank 500 is adjusted to control the flow rate between the piston hydraulic main pump 102 and the auxiliary hydraulic oil tank 500. The pressure provided by the proportional control solenoid valve 601 controls the size of the flow passage. The proportional control solenoid valve 601 is connected to the control unit at its control end, to the pilot gear pump 103 at its input end, and to the drive end of the first control valve 701 and the second control valve 702 at its output end. It is used to open under the control command generated by the control unit based on the oil suction status of the hydraulic oil supply unit and output pilot control oil to the first control valve 701 and the second control valve 702 so that the first control valve 701 and the second control valve 702 open synchronously.

[0039] In some alternative implementations, such as Figure 1 As shown, the system also includes: an oil level sensor 501 and an oil suction pressure sensor 801; the oil level sensor 501 is deployed in the auxiliary hydraulic oil tank 500 to detect the oil level in the auxiliary hydraulic oil tank 500; the oil suction pressure sensor 801 is deployed in the suction pipeline between the plunger hydraulic main pump 102 and the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500 to detect the suction pressure in the suction pipeline.

[0040] In some alternative implementations, such as Figure 1As shown, the execution unit 200 includes a control device 201 and an execution mechanism 202. The control device 201 is used to change the action of the execution mechanism 202 by controlling the opening and closing of the control valve core, such as a multi-way valve. A hydraulic oil cooling unit 900 is also included between the hydraulic oil return control unit 300 and the main hydraulic oil tank 400 to provide constant temperature protection for the hydraulic system. The main hydraulic oil tank 400 includes: a dipstick 401 for observing the oil level in the main hydraulic oil tank 400; a first return oil filter 402 for filtering impurities in the hydraulic oil; and a first suction oil filter 403 for filtering impurities in the hydraulic oil. The auxiliary hydraulic oil tank 500 includes: an oil level sensor 501 for continuously monitoring the oil level in the auxiliary hydraulic oil tank 500; a second return oil filter 502 for filtering impurities in the hydraulic oil; and a second suction oil filter 503 for filtering impurities in the hydraulic oil. One-way valves are included in the first control valve 701 and the second control valve 702 to establish pipeline pressure and prevent hydraulic oil backflow. A working pressure sensor 802 is deployed in the working pipeline between the hydraulic oil supply unit 100 and the execution unit 200 to detect the main pressure of the hydraulic pump in real time. This is used to assist in detection and judgment. When the pressure value of the working pressure sensor 802 is detected to be lower than 10MPa, it is a high flow demand state. The anti-vacuum strategy is already controlled to prevent the system from failing to detect the impact of damage to the oil suction pressure sensor 801 at the oil suction pipeline.

[0041] The hydraulic pump control system provided by this invention controls the working states of the hydraulic oil return control unit and the anti-vacuum control unit through a control unit. The anti-vacuum control unit controls the flow of hydraulic oil from the auxiliary hydraulic oil tank into the hydraulic oil supply unit. The hydraulic oil return control unit adjusts the direction of the return oil from the actuator, causing the return oil to enter the main hydraulic oil tank, or both the main and auxiliary hydraulic oil tanks. This allows the hydraulic oil supply unit to draw hydraulic oil from the main hydraulic oil tank, or both, to supply working oil to the actuator. By deploying the anti-vacuum control unit, this invention can control the hydraulic oil from the auxiliary hydraulic oil pump to participate in the hydraulic system circulation according to the working state of the hydraulic pump. Based on the physical structure, it achieves intelligent control of the hydraulic pump's oil intake, ensuring stable operation of the hydraulic pump under various working conditions, protecting the hydraulic pump, and thus ensuring the normal progress of engineering operations.

[0042] According to an embodiment of the present invention, a hydraulic pump control method embodiment is also provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0043] This embodiment provides a hydraulic pump control method, which can be used in the control unit of a hydraulic pump control system. Figure 2This is a flowchart of a hydraulic pump control method according to an embodiment of the present invention, such as... Figure 2 As shown, the process includes the following steps:

[0044] Step S201: Obtain the hydraulic oil demand of the execution unit, and control the hydraulic oil supply unit to draw in hydraulic oil according to the hydraulic oil demand to provide working oil for the execution unit.

[0045] Specifically, in embodiments of the present invention, such as Figure 1 As shown, the hydraulic pump control system includes: a hydraulic oil supply unit 100, an execution unit 200, a hydraulic oil return control unit 300, a main hydraulic oil tank 400, an auxiliary hydraulic oil tank 500, and an anti-vacuum control unit 600. The hydraulic pump control system also includes a control unit, but it is not shown in the diagram. Figure 1 This is reflected in the following: The hydraulic oil supply unit 100 is connected to the execution unit 200 via a working pipeline; the execution unit 200 is connected to the hydraulic oil return control unit 300, and the hydraulic oil return control unit 300 is connected to the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500 via return pipelines; the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500 are connected to the hydraulic oil supply unit 100 via suction pipelines.

[0046] In some alternative implementations, such as Figure 1 As shown, the hydraulic oil supply unit 100 includes a power unit 101, a plunger hydraulic main pump 102, and a pilot gear pump 103. Based on constant power control, in this embodiment of the invention, the control unit determines the hydraulic demand according to the load pressure of the execution unit 200, and then adjusts the power unit 101 according to the hydraulic demand, so that the power unit 101 provides the corresponding hydraulic energy to the plunger hydraulic main pump 102. The plunger hydraulic main pump 102 draws oil from the main hydraulic oil tank 400 or the auxiliary hydraulic oil tank 500, and draws hydraulic oil into the execution unit 200, thereby providing working oil for the execution unit 200. After the execution unit 200 (such as a hydraulic cylinder, hydraulic motor, etc.) completes its work under the action of the hydraulic oil, the hydraulic oil reaches the hydraulic oil return control unit 300 through the return oil pipeline.

[0047] Step S202: Control the working state of the hydraulic oil return control unit according to the return oil status of the actuator, so that the return oil of the actuator flows to the main hydraulic oil tank or the main hydraulic oil tank and the auxiliary hydraulic oil tank.

[0048] Specifically, in embodiments of the present invention, such as Figure 1As shown, the hydraulic oil return control unit 300 includes: a back pressure valve 301, which can establish hydraulic system return back pressure; a bypass valve 302, which can connect the main and auxiliary hydraulic oil tanks to return oil and prevent the system return pressure from being too high; it also includes: a first throttle valve 303, which can prevent pressure fluctuations after the back pressure valve is opened; and a second throttle valve 304, which can prevent pressure fluctuations after the bypass valve is opened and stabilize the system return back pressure.

[0049] In some optional embodiments, the control unit determines whether to open the back pressure valve 301 or open both the back pressure valve 301 and the bypass valve 302 based on the current pressure of the back pressure valve 301. During this process, the first throttle valve 303 and the second throttle valve 304 automatically adjust the pressure of the back pressure valve 301 or the bypass valve 302 by adjusting the return oil flow. When the return oil flow is small, only the back pressure valve 301 is opened, and the return oil can only flow into the main hydraulic oil tank 400 through the back pressure valve 301. When the return oil flow is large, the flow capacity of the back pressure valve 301 is insufficient to drain all the hydraulic oil, so both the back pressure valve 301 and the bypass valve 302 are opened simultaneously. The return oil is diverted through the back pressure valve 301 and the bypass valve 302, with one part flowing directly into the main hydraulic oil tank 400 and the other part flowing into the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500 respectively.

[0050] Step S203: Control the working state of the anti-air suction control unit according to the oil suction status of the hydraulic oil supply unit, so that the hydraulic oil from the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank, enters the hydraulic oil supply unit.

[0051] Specifically, in embodiments of the present invention, such as Figure 1 As shown, one end of the anti-cavitation control unit 600 is connected to the pilot gear pump 103, and the other end is connected to two control valves: a first control valve 701 and a second control valve 702. The first control valve 701 is located between the input end of the auxiliary hydraulic oil tank 500 and the bypass valve 302, and the second control valve 702 is located between the output end of the auxiliary hydraulic oil tank 500 and the hydraulic oil supply unit 100. Simultaneously, a suction pressure sensor 801 is installed on the suction pipeline between the output end of the auxiliary hydraulic oil tank 500 and the hydraulic oil supply unit 100 to detect the suction pressure. The suction pressure reflects the suction status of the hydraulic oil supply unit 100, and the suction status changes synchronously with the return status. If the suction pressure is too low, it indicates that there is insufficient hydraulic oil, and the return flow is too large, which may lead to cavitation.

[0052] In one alternative implementation, such as Figure 1As shown, the pilot gear pump 103 draws oil based on the hydraulic energy provided by the power unit 101, providing pilot control oil for the anti-vacuum control unit 600. In this embodiment of the invention, the working state of the anti-vacuum control unit 600 is adjusted according to the suction pressure. When the suction pressure is high, the anti-vacuum control unit 600 is not activated, and consequently, both the input and output ends of the auxiliary hydraulic oil tank 500 are disconnected. At this time, the return oil, after passing through the back pressure valve 301 and the bypass valve 302, all enters the main hydraulic oil tank 400. Only the hydraulic oil in the main hydraulic oil tank 400 can enter the plunger hydraulic main pump 102 through the suction pipeline; that is, only the hydraulic oil in the main hydraulic oil tank 400 needs to participate in the hydraulic circulation to meet the current working conditions.

[0053] In one optional implementation, when the suction pressure is low, it indicates that the demand for hydraulic oil is increasing and the return flow is increasing. The hydraulic oil in the main hydraulic oil tank 400 is insufficient to maintain the current working condition. At this time, the bypass valve 302 is opened, and the anti-vacuum control unit 600 is opened simultaneously. The pilot control oil flows to the first control valve 701 and the second control valve 702 after passing through the anti-vacuum control unit 600. The first control valve 701 and the second control valve 702 are opened under the pressure of the pilot control oil, thereby connecting the input and output ends of the auxiliary hydraulic oil tank 500. At this time, part of the return oil enters the main hydraulic oil tank 400 after passing through the back pressure valve 301, and the other part enters the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500 respectively after passing through the bypass valve 302. The hydraulic oil in the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500 can enter the piston hydraulic main pump 102 through the suction pipeline. That is, the hydraulic oil in the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500 participate in the hydraulic circulation together to meet the current working condition.

[0054] The hydraulic pump control method provided by this invention controls the working state of the hydraulic oil return control unit and the anti-vacuum control unit based on the return oil status and suction oil status. This ensures that the return oil from the actuator enters the main hydraulic oil tank, or both the main and auxiliary hydraulic oil tanks, allowing the hydraulic oil supply unit to draw hydraulic oil from the main hydraulic oil tank, or both, to supply working oil to the actuator. By deploying the anti-vacuum control unit and adjusting the control logic, this invention can control the hydraulic oil from the auxiliary hydraulic oil pump to participate in the hydraulic system circulation according to the working state of the hydraulic pump. Based on the physical structure, it achieves intelligent control of the hydraulic pump's oil suction, ensuring stable operation of the hydraulic pump under various working conditions, protecting the hydraulic pump, and thus ensuring the normal progress of engineering operations.

[0055] This embodiment provides a hydraulic pump control method, which can be used in the control unit of a hydraulic pump control system. Figure 3 This is a flowchart of hydraulic pump control according to an embodiment of the present invention, such as... Figure 3 As shown, the process includes the following steps:

[0056] Step S301: Obtain the hydraulic oil demand of the execution unit, and control the hydraulic oil supply unit to draw in hydraulic oil according to the hydraulic oil demand, providing working oil to the execution unit. For details, please refer to [link to relevant documentation]. Figure 2 Step S201 of the illustrated embodiment will not be described again here.

[0057] Step S302: Control the working state of the hydraulic oil return control unit according to the return oil status of the actuator, so that the return oil of the actuator flows to the main hydraulic oil tank or the main hydraulic oil tank and the auxiliary hydraulic oil tank.

[0058] Specifically, step S302 includes:

[0059] Step S3021: Obtain the current pressure of the back pressure valve and determine whether the current pressure is higher than the first preset pressure or the second preset pressure. The first preset pressure is less than the second preset pressure.

[0060] Specifically, in this embodiment of the invention, during the operation of the excavator, high-pressure hydraulic oil is supplied to the corresponding execution unit 200 of the working device through the plunger hydraulic main pump 102. The low-pressure area hydraulic oil of the execution unit 200 enters the hydraulic oil return control unit 300. The back pressure valve 301 in the hydraulic oil return control unit 300 establishes the return back pressure and determines whether the current pressure of the return back pressure reaches the first preset pressure, such as 0.5 bar, but not limited to this.

[0061] In step S3022, if the current pressure is higher than the first preset pressure, the back pressure valve is opened to allow the return oil to flow to the main hydraulic oil tank.

[0062] Specifically, in this embodiment of the invention, if the current pressure corresponding to the return oil back pressure reaches 0.5 bar, it proves that return oil exists at this time, and the return oil flow is small. It is necessary to open the back pressure valve 301 to allow the high-temperature hydraulic oil to enter the cooling system for heat dissipation before entering the main hydraulic oil tank 400. At this time, the flow capacity of the back pressure valve 301 is sufficient to drain all the return oil into the main hydraulic oil tank.

[0063] In some alternative embodiments, the back pressure valve 301 can be opened by the control unit, or the back pressure valve 301 can be opened automatically according to the pressure, which is not limited here.

[0064] In step S3023, if the current pressure is higher than the second preset pressure, when the back pressure valve is open, the bypass valve is controlled to open so that the return oil flows to the main hydraulic oil tank and the auxiliary hydraulic oil tank.

[0065] Specifically, in this embodiment of the invention, when the hydraulic demand of the execution unit 200 increases, the oil suction increases, and the return oil flow rate continues to increase, the flow capacity of the back pressure valve 301 is insufficient to drain all the hydraulic oil, resulting in an increase in the current pressure corresponding to the return oil back pressure. If the current pressure reaches a second preset pressure, for example, 2 bar, the bypass valve 302 is opened. At this time, the excess hydraulic oil flows to the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500 through the bypass valve. However, if... Figure 1 As shown, control valves are deployed at both ends of the auxiliary hydraulic oil tank 500. If the control valves are not open, all excess hydraulic oil will enter the main hydraulic oil tank 400. If the control valves are open, excess hydraulic oil will enter the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500 respectively.

[0066] Step S303: Control the working state of the anti-air suction control unit according to the oil suction status of the hydraulic oil supply unit, so that the hydraulic oil from the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank, enters the hydraulic oil supply unit.

[0067] Specifically, step S303 includes:

[0068] Step S3031: Obtain the oil suction pressure of the oil suction pipe and determine whether the oil suction pressure is lower than the third preset pressure or the fourth preset pressure. The third preset pressure is greater than the fourth preset pressure.

[0069] Specifically, in embodiments of the present invention, such as Figure 1 As shown, an oil suction pressure sensor 801 is deployed on the oil suction line. The control unit acquires the measured oil suction pressure of the oil suction line and determines whether the oil suction pressure is lower than a third preset pressure, such as 0.15 bar, but this is not a limit. At this time, the lower the oil suction pressure, the lower the oil suction volume. However, at this time, the return oil flow is large, which means that the hydraulic demand is increased. Since the hydraulic oil drawn by the piston hydraulic main pump 102 increases accordingly, if the oil suction volume is insufficient, it will cause the pressure in the oil suction line to drop. If no adjustment is made at this time, it may cause the hydraulic pump to suck in cavitation, resulting in negative pressure in the oil suction line.

[0070] In step S3032, if the suction pressure is not lower than the third preset pressure, the proportional control solenoid valve is closed so that the hydraulic oil in the main hydraulic oil tank enters the hydraulic oil supply unit.

[0071] Specifically, in embodiments of the present invention, such as Figure 1As shown, the anti-vacuum control unit 600 contains a proportional control solenoid valve 601. The control unit controls the opening and closing of the proportional control solenoid valve 601 based on the comparison between the suction pressure and the third preset pressure. If the suction pressure is not lower than 0.15 bar, it proves that there will be no vacuum, so the proportional control solenoid valve 601 is kept closed. If the proportional control solenoid valve 601 is closed, the pilot control oil cannot flow to the first control valve 701 and the second control valve 702, and the two ends of the auxiliary hydraulic oil tank 500 are not connected. Therefore, only the hydraulic oil in the main hydraulic oil tank 400 can enter the plunger hydraulic main pump 102 through the suction pipe and participate in the hydraulic circulation.

[0072] In step S3033, if the suction pressure is lower than the third preset pressure, the current opening degree of the solenoid valve is controlled according to the suction pressure control ratio so that the first control valve and the second control valve open synchronously, the return oil enters the auxiliary hydraulic oil tank according to the preset flow rate, and the hydraulic oil in the auxiliary hydraulic oil tank enters the hydraulic oil supply unit according to the preset flow rate.

[0073] Specifically, in this embodiment of the invention, if the suction pressure is lower than 0.15 bar, it indicates that cavitation may occur. Therefore, the proportional control solenoid valve 601 is opened. If the proportional control solenoid valve 601 is opened, the pilot control oil flows to the first control valve 701 and the second control valve 702. The first control valve 701 and the second control valve 702 open synchronously under the pressure of the pilot control oil, and the two ends of the auxiliary hydraulic oil tank 500 are connected. Therefore, the return oil can enter the auxiliary hydraulic oil tank 500. The hydraulic oil in the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500 can simultaneously enter the plunger hydraulic main pump 102 through the suction pipeline and participate in the hydraulic circulation.

[0074] In some optional embodiments, the proportional control solenoid valve is a hydraulic component that precisely controls the flow, pressure, or direction of hydraulic oil via electrical signals. Therefore, the control unit can control the current value supplied to the proportional control solenoid valve 601 according to the suction pressure. Different current values ​​(e.g., current values ​​of 200mA-600mA, where 200mA represents opening and 600mA represents full opening) result in different opening degrees of the proportional control solenoid valve 601. This, in turn, controls the flow rate of the pilot control oil and synchronously controls the opening degrees of the first control valve 701 and the second control valve 702, so that the return oil enters the auxiliary hydraulic oil tank 500 at the corresponding flow rate, and the hydraulic oil in the auxiliary hydraulic oil tank 500 enters the hydraulic oil supply unit 100 at the same flow rate. That is, the return oil volume and suction oil volume of the auxiliary hydraulic oil tank 500 are kept synchronized.

[0075] In step S3034, if the suction pressure is lower than the fourth preset pressure, the proportional control solenoid valve is opened to the maximum opening degree so that the first control valve and the second control valve are opened to the maximum opening degree simultaneously. The return oil enters the auxiliary hydraulic oil tank at the maximum flow rate, and the hydraulic oil in the auxiliary hydraulic oil tank enters the hydraulic oil supply unit at the maximum flow rate.

[0076] Specifically, in this embodiment of the invention, if the suction pressure continues to decrease, it indicates that the demand for hydraulic oil is continuously increasing. To prevent cavitation, the suction volume needs to be increased. Therefore, if the suction pressure is lower than the fourth preset pressure, for example, -0.25 bar, the control unit controls the proportional control solenoid valve 601 to open to its maximum opening. Consequently, the pilot control oil acts on the first control valve 701 and the second control valve 702 at its maximum flow rate, causing the first control valve 701 and the second control valve 702 to open to their maximum opening rates simultaneously. At this time, the return oil enters the auxiliary hydraulic oil tank 500 at its maximum flow rate, and the hydraulic oil in the auxiliary hydraulic oil tank 500 enters the hydraulic oil supply unit 100 at the same maximum flow rate. That is, the return oil volume and suction oil volume of the auxiliary hydraulic oil tank 500 are always kept synchronized.

[0077] In some optional embodiments, to ensure that the return and intake oil volumes of the auxiliary hydraulic oil tank 500 remain synchronized and that the oil level in the auxiliary hydraulic oil tank 500 is always maintained at the optimal position, an oil level sensor 501 is deployed in the auxiliary hydraulic oil tank 500 to detect the real-time oil level. If the real-time oil level changes, an alarm signal is generated. Oil level detection prevents situations where the first control valve 701 and the second control valve 702 malfunction but are not easily detected, leading to changes in the oil level. For example, it prevents situations where only return oil is present and the second control valve 702 fails unexpectedly, causing hydraulic oil to overflow from the auxiliary hydraulic oil tank 500; it also prevents situations where only intake oil is present and the first control valve 701 fails unexpectedly, causing the hydraulic oil in the auxiliary hydraulic oil tank 500 to be sucked dry, resulting in high negative pressure and damage to the auxiliary hydraulic oil tank 500 and the hydraulic pump.

[0078] Step S3035: Determine whether the oil suction pressure is lower than the fifth preset pressure. If the fifth preset pressure is lower than the fourth preset pressure, adjust the control strategy and generate a second alarm signal.

[0079] Specifically, in this embodiment of the invention, considering extreme cases, that is, if the main hydraulic oil tank 400 and the auxiliary hydraulic oil tank 500 participate in the hydraulic cycle at their maximum capacity but still cannot meet the current hydraulic oil demand, the suction pressure will continue to decrease. When it drops to the fifth preset pressure, such as the minimum pressure value required by the hydraulic pump -0.5 bar, an alarm signal is generated in time, and the control strategy is adjusted at the same time, such as by reducing the displacement of the hydraulic pump to reduce the flow rate required by the hydraulic pump.

[0080] The hydraulic pump control method provided by this invention controls the working state of the hydraulic oil return control unit and the anti-vacuum control unit based on the return oil status and suction oil status. This ensures that the return oil from the actuator enters the main hydraulic oil tank, or both the main and auxiliary hydraulic oil tanks, allowing the hydraulic oil supply unit to draw hydraulic oil from the main hydraulic oil tank, or both, to supply working oil to the actuator. By deploying the anti-vacuum control unit and adjusting the control logic, this invention can control the hydraulic oil from the auxiliary hydraulic oil pump to participate in the hydraulic system circulation according to the working state of the hydraulic pump. Based on the physical structure, it achieves intelligent control of the hydraulic pump's oil suction, ensuring stable operation of the hydraulic pump under various working conditions, protecting the hydraulic pump, and thus ensuring the normal progress of engineering operations.

[0081] This invention also provides an engineering machinery device, including the above-mentioned... Figure 1 The hydraulic pump control system shown is used in, for example, excavators.

[0082] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A hydraulic pump control system, characterized in that, include: Control unit, hydraulic oil supply unit, execution unit, hydraulic oil return control unit, main hydraulic oil tank, auxiliary hydraulic oil tank and anti-vacuum control unit; The hydraulic oil supply unit has an input end connected to the main hydraulic oil tank and the auxiliary hydraulic oil tank, and an output end connected to the first end of the execution unit. It is used to draw hydraulic oil from the main hydraulic oil tank or the main hydraulic oil tank and the auxiliary hydraulic oil tank to provide working oil for the execution unit. The hydraulic oil return control unit includes a back pressure valve and a bypass valve. The first end of the back pressure valve is connected to the execution unit, and the second end is connected to the main hydraulic oil tank. The first end of the bypass valve is connected to the execution unit, and the second end is connected to the main hydraulic oil tank and the auxiliary hydraulic oil tank. The hydraulic oil return control unit is used to adjust the direction of the return oil from the execution unit, so that the return oil flows to the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank. The system further includes: a first control valve and a second control valve, wherein a first end of the first control valve is connected to the input end of the auxiliary hydraulic oil tank and a second end is connected to the second end of the bypass valve; a first end of the second control valve is connected to the output end of the auxiliary hydraulic oil tank and a second end is connected to the plunger hydraulic main pump and the pilot gear pump of the hydraulic oil supply unit. The anti-vacuum control unit includes: a proportional control solenoid valve; the control terminal of the proportional control solenoid valve is connected to the control unit, the input terminal is connected to the pilot gear pump, and the output terminal is connected to the drive terminal of the first control valve and the drive terminal of the second control valve. The anti-vacuum control unit is used to control the hydraulic oil in the auxiliary hydraulic oil tank to enter the hydraulic oil supply unit. The control unit is connected to the hydraulic oil return control unit and the anti-vacuum control unit, and is used to control the working status of the hydraulic oil return control unit and the anti-vacuum control unit.

2. The system according to claim 1, characterized in that, The hydraulic oil supply unit includes: a power unit, a piston hydraulic main pump, and a pilot gear pump; The power unit is connected to the drive end of the plunger hydraulic main pump and the drive end of the pilot gear pump, and is used to provide hydraulic energy to the plunger hydraulic main pump and the pilot gear pump. The plunger hydraulic main pump has its input end connected to the main hydraulic oil tank and the auxiliary hydraulic oil tank, and its output end connected to the execution unit. It is used to draw hydraulic oil from the main hydraulic oil tank or the main hydraulic oil tank and the auxiliary hydraulic oil tank to provide working oil for the execution unit. The pilot gear pump has its input end connected to the main hydraulic oil tank and the auxiliary hydraulic oil tank, and its output end connected to the anti-vacuum control unit. It is used to draw hydraulic oil from the main hydraulic oil tank or the main hydraulic oil tank and the auxiliary hydraulic oil tank to provide pilot control oil for the anti-vacuum control unit.

3. The system according to claim 2, characterized in that, The back pressure valve is used to open when the current pressure of the back pressure valve reaches a first preset pressure, so that the return oil flows to the main hydraulic oil tank. The bypass valve is used to open when the current pressure of the back pressure valve reaches a second preset pressure, so that the return oil flows to the main hydraulic oil tank and the auxiliary hydraulic oil tank.

4. The system according to claim 3, characterized in that, The first control valve is used to adjust the hydraulic oil input of the auxiliary hydraulic oil tank; The second control valve is used to adjust the hydraulic oil output of the auxiliary hydraulic oil tank; The proportional control solenoid valve is used to open under the control command generated by the control unit based on the oil suction status of the hydraulic oil supply unit, and output the pilot control oil to the first control valve and the second control valve so that the first control valve and the second control valve open synchronously.

5. The system according to any one of claims 2 to 4, characterized in that, The system also includes: an oil level sensor and an oil suction pressure sensor; The oil level sensor is deployed in the auxiliary hydraulic oil tank and is used to detect the oil level in the auxiliary hydraulic oil tank; The oil suction pressure sensor is deployed in the oil suction line between the plunger hydraulic main pump and the main hydraulic oil tank and the auxiliary hydraulic oil tank, and is used to detect the oil suction pressure of the oil suction line.

6. A hydraulic pump control method for a system as described in any one of claims 1-5, characterized in that, The method includes: The hydraulic oil demand of the execution unit is obtained, and the hydraulic oil supply unit is controlled to draw in hydraulic oil according to the hydraulic oil demand to provide working oil to the execution unit; The working state of the hydraulic oil return control unit is controlled according to the return oil status of the actuator, so that the return oil of the actuator flows to the main hydraulic oil tank or the main hydraulic oil tank and the auxiliary hydraulic oil tank. The operating state of the anti-air suction control unit is controlled according to the oil suction status of the hydraulic oil supply unit, so that the hydraulic oil from the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank, enters the hydraulic oil supply unit.

7. The method according to claim 6, characterized in that, The hydraulic oil return control unit includes: a back pressure valve and a bypass valve; The operating state of the hydraulic oil return control unit is controlled according to the return oil status of the actuator, so that the return oil from the actuator flows to the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank, including: The current pressure of the back pressure valve is obtained, and it is determined whether the current pressure is higher than a first preset pressure or a second preset pressure, wherein the first preset pressure is less than the second preset pressure; If the current pressure is higher than the first preset pressure, the back pressure valve is opened to allow the return oil to flow to the main hydraulic oil tank. If the current pressure is higher than the second preset pressure, then when the back pressure valve is opened, the bypass valve is controlled to open so that the return oil flows to the main hydraulic oil tank and the auxiliary hydraulic oil tank.

8. The method according to claim 6, characterized in that, The hydraulic pump control system further includes: a first control valve and a second control valve; the anti-vacuum control unit includes: a proportional control solenoid valve; and a suction pressure sensor is deployed on the suction pipeline between the hydraulic oil supply unit, the main hydraulic oil tank, and the auxiliary hydraulic oil tank. The operating state of the anti-air suction control unit is controlled according to the oil suction status of the hydraulic oil supply unit, so that hydraulic oil from the main hydraulic oil tank, or the main hydraulic oil tank and the auxiliary hydraulic oil tank, enters the hydraulic oil supply unit, including: The oil suction pressure of the oil suction pipe is obtained, and it is determined whether the oil suction pressure is lower than a third preset pressure or a fourth preset pressure, wherein the third preset pressure is greater than the fourth preset pressure; If the oil suction pressure is not lower than the third preset pressure, then the proportional control solenoid valve is closed so that the hydraulic oil in the main hydraulic oil tank enters the hydraulic oil supply unit. If the suction pressure is lower than the third preset pressure, the current opening of the proportional control solenoid valve is controlled according to the suction pressure so that the first control valve and the second control valve open synchronously, the return oil enters the auxiliary hydraulic oil tank according to the preset flow rate, and the hydraulic oil in the auxiliary hydraulic oil tank enters the hydraulic oil supply unit according to the preset flow rate. If the suction pressure is lower than the fourth preset pressure, the proportional control solenoid valve is controlled to open to the maximum opening degree, so that the first control valve and the second control valve open to the maximum opening degree simultaneously. The return oil enters the auxiliary hydraulic oil tank at the maximum flow rate, and the hydraulic oil in the auxiliary hydraulic oil tank enters the hydraulic oil supply unit at the maximum flow rate.

9. The method according to claim 8, characterized in that, The auxiliary hydraulic oil tank is equipped with an oil level sensor. In controlling the operation of the anti-vacuum control unit based on the oil suction status of the hydraulic oil supply unit, so that hydraulic oil from the main hydraulic oil tank, or both the main and auxiliary hydraulic oil tanks, enters the hydraulic oil supply unit, the process further includes: The real-time oil level of the auxiliary hydraulic oil tank is obtained, and it is determined whether the real-time oil level has changed. If it has changed, a first alarm signal is generated. Determine whether the oil suction pressure is lower than the fifth preset pressure. If the fifth preset pressure is lower than the fourth preset pressure, adjust the control strategy and generate a second alarm signal.

10. An engineering machinery equipment, characterized in that, The hydraulic pump control system includes any one of claims 1 to 5.

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