Hydraulic test system and method for electro-hydraulic servo element

Abstract

The invention discloses a hydraulic test system and method for an electro-hydraulic servo element. The system comprises a rack, and an oil tank assembly, a power module, a hydraulic module, a loading module, a feedback module and a main control module which are arranged on the rack. The hydraulic module realizes accurate control of pressure and flow, and provides stable hydraulic control support for the tested element. The loading module is connected with a one-way valve and an overflow valve through a flow channel in the second integrated block to form a bridge circuit channel of the loading oil cylinder, so that loading and oil supplementation of the loading oil cylinder are realized, and the load test requirement is met. The power module provides stable hydraulic oil for the tested element and the loading oil cylinder through the oil supply unit and the oil supplementing unit. And the feedback module adopts a tension and pressure sensor, a follow-up piston displacement sensor and a valve core position sensor to directly acquire the valve core position, force and displacement data of the tested element, so that the interference of closed-loop test is avoided. According to the system, through modular design and accurate control, multiple test requirements of the electro-hydraulic servo element can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic testing, and in particular to a hydraulic testing system and method for an electro-hydraulic servo element. Background Art

[0002] The hydraulic test system is a device used to test and evaluate hydraulic components (such as hydraulic valves, hydraulic cylinders, pumps, motors, etc.) and their performance. It simulates different working conditions by controlling the pressure, flow, load and other parameters of the hydraulic oil, collects data from the hydraulic system or hydraulic components in operation, and analyzes their working status, dynamic response and reliability.

[0003] The invention patent CN114060355A provides a hydraulic test system, including an ultra-high pressure test oil circuit, a first low, medium and high pressure test oil circuit and a flushing pipeline oil circuit, a first motor pump group and a second motor pump group. Various working conditions can be tested on the ultra-high pressure test oil circuit, the first low, medium and high pressure test oil circuit and the flushing pipeline oil circuit, which can effectively improve the test efficiency. In particular, the flushing pipeline oil circuit for flushing the pipeline can effectively clean the hydraulic pipeline, extend the service life of the pipeline, reduce hydraulic oil pollution and improve the test accuracy.

[0004] However, although the hydraulic test system in the CN114060355A patent has multi-condition test capabilities and improves pipeline cleanliness by setting up ultra-high pressure test oil circuits, low, medium and high pressure test oil circuits and pipeline flushing oil circuits, the system lacks direct measurement methods and open-loop test designs for key parameters such as dynamic characteristics, valve core position, and flow rate of electro-hydraulic servo components. It cannot simulate complex working conditions or provide real-time load adjustment, and cannot meet the testing requirements for electro-hydraulic servo components. Summary of the invention

[0005] Based on this, it is necessary to provide an electro-hydraulic servo component hydraulic test system and method to address the problem that the technical solution of the above patent cannot meet the test requirements for electro-hydraulic servo components.

[0006] The present application provides an electro-hydraulic servo component hydraulic test system, comprising a frame and an oil tank assembly, a power module, a hydraulic module, a loading module, a feedback module and a main control module arranged on the frame.

[0007] The frame includes a base and a stand;

[0008] The hydraulic module is arranged on the base, and includes a first integrated block, and a first overflow valve, a safety valve, a flow valve, a first stop valve, an electro-hydraulic reversing valve, a throttle valve, and a back pressure valve arranged on the first integrated block. The first overflow valve, the safety valve, the flow valve, the first stop valve, the electro-hydraulic reversing valve, the throttle valve, and the back pressure valve are connected through a flow channel arranged in the first integrated block. The hydraulic module is used to control the pressure change of the hydraulic source and the movement of the valve core of the driving pressure regulating valve of the test element, and is also used to provide back pressure for the test element;

[0009] The loading module is arranged on the base, and includes a second integrated block and a loading oil cylinder, and four first one-way valves, a second overflow valve, and a first pressure gauge arranged on the second integrated block. The four first one-way valves, the second overflow valve, the first pressure gauge, and the loading oil cylinder are connected through a flow channel arranged in the second integrated block, and the loading module is connected to the power module; the four one-way valves constitute a bridge channel in two directions of extension and retraction of the loading oil cylinder, and provide a loading and oil replenishment channel for the loading oil cylinder;

[0010] The power module includes an oil supply unit for supplying oil to the test element and an oil replenishing unit for replenishing oil to the loading cylinder, the oil supply unit and the oil replenishing unit are respectively connected to the oil tank assembly to draw oil from the oil tank assembly, and the hydraulic module and the power module are also used to provide a constant pressure dynamically switched parallel hydraulic source for the test element;

[0011] The test element and the loading cylinder are arranged on the stand, the feedback module is arranged between the piston rod of the follower differential cylinder of the test element and the piston rod of the loading cylinder, the feedback module comprises a tension pressure sensor, a follower piston displacement sensor and a valve core position sensor, and the valve core position sensor is arranged on the valve core of the follower differential cylinder of the test element;

[0012] The main control module includes a control unit connected to the power module and the hydraulic module, a collection unit and a processing unit connected to the tension and pressure sensor, the follower piston displacement sensor and the valve core position sensor. The control unit is used to control the power module and the hydraulic module, and the collection unit and the processing unit are used to collect and process the valve core position, force, displacement and flow data of the test element.

[0013] Optionally, the first overflow valve, the safety valve, the flow valve, and one end valve ports of the first stop valve are connected in parallel and are respectively connected to the P port of the electro-hydraulic reversing valve and the interface of the first integrated block connected to the loading module;

[0014] The other end valve ports of the first overflow valve, the safety valve, the flow valve, and the stop valve are in communication with the interface of the first integrated block connected to the oil tank assembly;

[0015] The T port of the electro-hydraulic reversing valve is connected to the inlet of the back pressure valve, the A port of the electro-hydraulic reversing valve is also connected to a high-pressure filter, and is connected to a pressure valve port of the tested element through the high-pressure filter and the throttle valve, and the B port of the electro-hydraulic reversing valve is connected to another pressure valve port of the tested electro-hydraulic servo element through the first integrated block;

[0016] The outlet of the back pressure valve on the first integrated block is connected to the upper interface of the oil tank assembly.

[0017] Optionally, four first one-way valves are connected in pairs in sequence through the flow channel inside the second integrated block; the first ends of the first one-way valves connected in pairs are connected to the interface of the second integrated block connected to the hydraulic module; the second ends of the first one-way valves connected in pairs are connected to the second relief valve and the first pressure gauge; the third ends and the fourth ends of the first one-way valves connected in pairs are respectively connected to the interfaces of the second integrated block connected to the two oil ports of the loading cylinder;

[0018] The outlet of the overflow valve on the second integrated block is connected to the upper interface of the oil tank assembly.

[0019] Optionally, the oil supply unit is arranged on the base, including a first oil inlet filter arranged in parallel, a first oil pump motor arranged in parallel, a second one-way valve and a first pressure line filter arranged in parallel, and the first oil inlet filter, the first oil pump motor, the second one-way valve and the pressure line filter are connected in sequence.

[0020] Optionally, the oil replenishing unit is arranged on the base, and includes an oil inlet filter, a second oil pump motor, a third one-way valve and a second pressure line filter connected in sequence, and the second oil pump motor is connected to the oil tank assembly; the outlet of the second oil pump motor is connected to a valve module, and the valve module includes a loading overflow valve, an electromagnetic reversing valve, a second stop valve, and a second pressure gauge, the outlet of the loading overflow valve is connected to the oil tank, one way of the oil circuit outlet of the valve module is connected to the working oil port of the electromagnetic reversing valve, and the other way of the oil circuit outlet of the valve module is connected to the outlet of the second stop valve.

[0021] Optionally, an accumulator is provided at the outlet of the oil supply module, and the accumulator group is arranged on the base. The accumulator is also connected to the hydraulic module and is used to maintain a constant oil supply pressure when the oil supply module switches the oil supply source, provide a supplement to the instantaneous flow demand, and smooth out pressure pulsations.

[0022] Optionally, the hydraulic module also includes a pressure relay, a third pressure gauge and a damper. The pressure relay is used to detect the pressure threshold of the hydraulic test system. When the pressure of the hydraulic test system reaches a set high pressure threshold, the microswitch of the pressure relay is energized. The pressure relay sends the microswitch energization signal to the main control module, and the main control module controls the oil pump motor to shut down. When the pressure of the hydraulic test system suddenly drops and reaches a set low pressure threshold, the pressure relay outputs a signal to the main control module, and the main control module controls the switching between the oil pump motor groups. The damper is used to smooth out the pressure pulse impact in the hydraulic module.

[0023] Optionally, the oil tank assembly includes an oil tank body, a flow meter, a fourth one-way valve, a cooler, a temperature relay, an electromagnetic water valve and an oil return filter;

[0024] The temperature relay is arranged outside the oil tank body and is used to detect the temperature of the oil tank body. The cooler is arranged on the top surface of the oil tank body. The inlet of the cooler is connected to the oil return port of the hydraulic module. The outlet of the cooler is connected to the flow meter and the fourth one-way valve in sequence. The electromagnetic water valve is used to control the on-off of the external water supply pump to supply water to the cooler.

[0025] The oil tank body is also provided with a liquid level control relay for detecting the oil height in the oil tank body. The oil tank body is also provided with an air filter for maintaining the balance between the oil tank body and the atmospheric pressure and filtering the air entering the oil tank body.

[0026] Optionally, a pressure differential transmitter is provided in the first pressure line filter, the second pressure line filter and the return oil filter, and the pressure differential transmitter is used to detect the blockage of the first pressure line filter, the second pressure line filter and the return oil filter, and to warn the main control module.

[0027] The present application also provides a hydraulic test method for an electro-hydraulic servo component, including the above-mentioned hydraulic test system for an electro-hydraulic servo component, and also includes the following experimental process:

[0028] Setting of the test element: The test element and the loading cylinder are set at the upper and lower ends of the stand, the follower differential cylinder piston rod of the test element is connected with the piston rod of the loading cylinder, and a tension pressure sensor and a follower piston displacement sensor are set between the follower differential cylinder piston rod of the test element and the piston rod of the loading cylinder, and the valve core position sensor is set on the control valve core of the test element;

[0029] Input of control signals: The control unit of the main control module sends control signals to the hydraulic module, power module and the tested components;

[0030] Oil supply and loading of the tested component: The hydraulic oil in the oil tank is transported to the P port of the electro-hydraulic reversing valve through the first motor oil pump group in the oil supply unit. The electro-hydraulic reversing valve maintains the valve position unchanged after being energized to switch the electro-hydraulic reversing valve to the working left position. The hydraulic oil flows out from the A port of the electro-hydraulic reversing valve, passes through the first oil inlet filter and the throttle valve, and enters the upper and lower chambers of the follower piston of the tested component. The up and down movement of the follower piston of the tested component and the hydraulic oil pressure difference are controlled by adjusting the size and direction of the input current;

[0031] When the input current of the control unit gradually increases, the pressure of the variable throttle port on the follower piston increases, and the hydraulic oil pushes the follower piston to move downward. The hydraulic oil flows through the T port of the electro-hydraulic reversing valve, the back pressure valve, the flow meter, the check valve and the filter, and finally flows back to the oil tank;

[0032] When the input current gradually decreases to zero, the follower piston stops moving and maintains the current position; at this time, the flow of hydraulic oil is balanced through the power source, electro-hydraulic reversing valve, back pressure valve and throttle valve to keep the pressure constant;

[0033] When the input current increases in the reverse direction, the pressure of the variable throttle port under the follower piston increases, and the hydraulic oil pushes the follower piston upward. The hydraulic oil flows through the T port of the electro-hydraulic reversing valve, the back pressure valve, the flow meter, the check valve and the filter, and finally flows back to the oil tank;

[0034] Oil replenishment and loading of the loading cylinder: The hydraulic oil in the oil tank is transported to the P port of the electromagnetic reversing valve of the loading module through the second motor oil pump group in the loading oil replenishment power module. After the electromagnetic reversing valve is energized and in the left position, the valve position remains unchanged, so that the hydraulic oil flows out from the A port of the electromagnetic reversing valve, passes through the loading overflow valve and the one-way valve bridge channel in the loading module, and the replenishing oil enters the forward volume of the loading cylinder. The piston rod of the loading cylinder moves outward under the drag of the tested electro-hydraulic servo element; at the same time, the hydraulic oil in the backward volume of the loading cylinder is squeezed and flows back to the oil tank through the one-way valve and the loading overflow valve;

[0035] During the oil replenishment and loading process, the oil supply pressure of the loading cylinder is set unchanged by the power module overflow valve, and the loading overflow valve adjusts the loading pressure of the loading cylinder in real time until the loading pressure reaches the load pressure value required by the test; the main control module monitors the loading pressure value through the control unit, and when the tested electro-hydraulic servo element reaches the specified position or the adjusted loading pressure exceeds the actual required value, the loading cylinder stops moving;

[0036] Collection and processing of test component parameters: The collection unit of the main control module collects the load force signal, piston displacement signal and valve core position signal fed back by the tension and pressure sensor, follow-up piston displacement sensor and valve core position sensor in real time. The processing unit generates various characteristic curves of the test component based on the load force parameters, valve core position parameters, piston displacement parameters of the test component and the flow parameters obtained based on the piston displacement parameters.

[0037] Compared with the prior art, the technical solution provided by this application has the following beneficial effects:

[0038] The above-mentioned electro-hydraulic servo component hydraulic test system meets the multiple functional test requirements of the test element through the mutual cooperation of the hydraulic module, the loading module, the power module and the feedback module. The hydraulic module realizes the precise control of pressure and flow through the flow channel connection in the first integrated block, provides stable hydraulic control support for the test element, and provides back pressure to adapt to various test conditions. The loading module forms a bridge channel of the loading cylinder through the one-way valve and the overflow valve connected through the flow channel in the second integrated block, realizes the loading and oil replenishment of the loading cylinder, and meets the load test requirements. The power module provides stable hydraulic oil to the test element and the loading cylinder through the oil supply unit and the oil replenishment unit. The feedback module adopts a tension pressure sensor, a follower piston displacement sensor and a valve core position sensor. The valve core position sensor is set on the valve core of the pressure regulating valve of the test element, and directly collects the valve core position, force and displacement data of the test element to avoid interference from the closed-loop test. The main control module is responsible for controlling the power module and the hydraulic module, and at the same time collects and processes the test data to ensure the accuracy and reliability of the test. Through modular design and precise control, this system can meet multiple test requirements of electro-hydraulic servo components. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A hydraulic principle diagram of a hydraulic test system for a hydraulic servo element provided in one embodiment of the present application;

[0040] Figure 2 A front view of a hydraulic test system for a hydraulic servo element provided in one embodiment of the present application;

[0041] Figure 3 A top view of a hydraulic test system for a hydraulic servo element provided in one embodiment of the present application.

[0042] Description of reference numerals:

[0043] 1. Fuel tank assembly; 2. First oil inlet filter; 3. Accumulator; 4. First oil pump motor; 5. Second check valve; 6. Flow valve; 7. First pressure line filter; 8. Back pressure valve; 9. Electro-hydraulic reversing valve; 10. Third pressure gauge; 11. Pressure sensor; 12. Pressure relay; 13. High pressure filter; 14. Throttle valve; 15. Test element; 16. Loading cylinder; 17. Pull pressure sensor; 18. Displacement sensor; 19. Position sensor; 20. First pressure gauge; 21. First check valve; 22. Second relief valve; 23. First relief valve; 24 , safety valve; 25, flow meter; 26, fourth one-way valve; 27, solenoid reversing valve; 28, second pressure gauge; 29, return oil filter; 30, second pressure line filter; 31, third one-way valve; 32, loading relief valve; 33, second oil pump motor unit; 34, solenoid water valve; 35, cooler; 36, second oil inlet filter; 37, temperature relay; 38, liquid level control relay; 39, air filter; 40, hydraulic module; 41, oil replenishment unit; 42, main control module; 43, oil supply unit; 44, loading module; 45, stand; 46, base. DETAILED DESCRIPTION

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0045] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0046] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0047] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0049] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0050] See also Figures 1 to 3 An embodiment of the present invention provides a hydraulic test system for an electro-hydraulic servo element, comprising a frame, an oil tank assembly 1 arranged on the frame, a power module, a hydraulic module 40, a loading module 44, a feedback module and a main control module 42.

[0051] The frame includes a base 46 and a stand 45;

[0052] The hydraulic module 40 is arranged on the base 46, and includes a first integrated block, and a first overflow valve 23, a safety valve 24, a flow valve 6, a first stop valve, an electro-hydraulic reversing valve 9, a throttle valve 14, and a back pressure valve 8 arranged on the first integrated block. The first overflow valve 23, the safety valve 24, the flow valve 6, the first stop valve, the electro-hydraulic reversing valve 9, the throttle valve 14, and the back pressure valve 8 are connected through a flow channel arranged in the first integrated block. The hydraulic module 40 is used to control the pressure change of the hydraulic source and the movement of the valve core of the driving pressure regulating valve of the test element 15, and is also used to provide back pressure for the test element 15;

[0053] The loading module 44 is arranged on the base 46, and includes a second integrated block and a loading oil cylinder, and four first one-way valves 21, a second overflow valve 22, and a first pressure gauge 20 arranged on the second integrated block. The four first one-way valves 21, the second overflow valve 22, the first pressure gauge 20 and the loading oil cylinder are connected through a flow channel arranged in the second integrated block, and the loading module 44 is connected to the power module; the four one-way valves constitute a bridge channel in two directions of extension and retraction of the loading oil cylinder, and provide a loading and oil replenishing channel for the loading oil cylinder;

[0054] The power module includes an oil supply unit 43 for supplying oil to the test element 15 and an oil replenishment unit 41 for replenishing oil to the loading cylinder. The oil supply unit 43 and the oil replenishment unit 41 are respectively connected to the oil tank assembly 1 to draw oil from the oil tank assembly 1. The hydraulic module 40 and the power module are also used to provide a constant pressure dynamically switched parallel hydraulic source for the test element 15;

[0055] The test element 15 and the loading cylinder are arranged on a stand 45, and a feedback module is arranged between the piston rod of the follower differential cylinder of the test element 15 and the piston rod of the loading cylinder. The feedback module includes a tension and pressure sensor 17, a follower piston displacement sensor 18 and a valve core position sensor 19 which are connected in sequence. The valve core position sensor 19 is arranged on the valve core of the follower differential cylinder of the test element 15;

[0056] The main control module 42 includes a control unit connected to the power module and the hydraulic module 40, a collection unit connected to the tension and pressure sensor 17, the follower piston displacement sensor 18 and the valve core position sensor 19, and a processing unit. The control unit is used to control the power module and the hydraulic module 40, and the collection unit and the processing unit are used to collect and process the valve core position, force, displacement and flow data of the test element 15.

[0057] The electro-hydraulic servo element hydraulic test system provided by the embodiment of the present invention meets the requirements of multiple functional tests of the test element 15 through the mutual cooperation of the hydraulic module 40, the loading module 44, the power module and the feedback module. The hydraulic module 40 realizes precise control of pressure and flow through the flow channel connection in the first integrated block, provides stable hydraulic support for the test element 15, and provides back pressure to adapt to various test conditions. The loading module 44 forms a bridge channel of the loading cylinder through the one-way valve and the overflow valve connected through the flow channel in the second integrated block, realizes loading and oil replenishment of the loading cylinder, and meets the load test requirements. The power module provides stable hydraulic oil to the test element 15 and the loading cylinder through the oil supply unit 43 and the oil replenishment unit 41. The feedback module adopts the tension pressure sensor 17, the follower piston displacement sensor 18 and the valve core position sensor 19 to directly collect the valve core position, force and displacement data of the test element 15 to avoid interference from the closed-loop test. The main control module 42 is responsible for controlling the power module and the hydraulic module 40, and at the same time collects and processes the test data to ensure the accuracy and reliability of the test. Through modular design and precise control, this system can meet multiple test requirements of electro-hydraulic servo components.

[0058] In the hydraulic test system of the electro-hydraulic servo element provided in this embodiment, the first relief valve 23, the safety valve 24, the flow valve 6, and one end valve port of the first stop valve are connected in parallel, and are respectively connected to the P port of the electro-hydraulic reversing valve 9 and the interface of the first integrated block connecting the loading module 44;

[0059] The first overflow valve 23, the safety valve 24, the flow valve 6, and the other end valve ports of the stop valve are connected to the interface of the first integrated block connected to the oil tank assembly 1;

[0060] The T port of the electro-hydraulic reversing valve 9 is connected to the inlet of the back pressure valve 8, the A port of the electro-hydraulic reversing valve 9 is also connected to the high pressure filter 13, and is sequentially connected to a pressure valve port of the tested element 15 through the high pressure filter 13 and the throttle valve 14, and the B port of the electro-hydraulic reversing valve 9 is connected to another pressure valve port of the tested electro-hydraulic servo element through the first integrated block;

[0061] The outlet of the back pressure valve 8 on the first integrated block is connected to the oil tank assembly 1 .

[0062] In this embodiment, by setting a first integrated block, the flow channels of the first overflow valve 23, the safety valve 24, the flow valve 6, the first stop valve, the electro-hydraulic reversing valve 9, the throttle valve 14 and the back pressure valve 8 are integrated to form a pipeless connection, which not only simplifies the connection path between the hydraulic valves and reduces the complexity of the pipeline layout, but also improves the reliability of the system, reduces the risk of oil leakage, further optimizes the spatial layout of the system, makes the system structure more compact, and meets the requirements of efficient and reliable hydraulic test equipment.

[0063] In the hydraulic test system of the electro-hydraulic servo element provided in this embodiment, four first one-way valves 21 are connected in pairs in sequence through the flow channel inside the second integrated block; the first ends of the first one-way valves 21 connected in pairs are connected to the interface of the second integrated block connected to the hydraulic module 40; the second ends of the first one-way valves 21 connected in pairs are connected to the second overflow valve 22 and the first pressure gauge 20; the third and fourth ends of the first one-way valves 21 connected in pairs are respectively connected to the interfaces of the two oil ports of the loading cylinder of the second integrated block; and the outlet of the overflow valve on the second integrated block is connected to the oil tank assembly 1.

[0064] In this embodiment, four first one-way valves 21 are connected in pairs through the internal flow channel of the second integrated block of the loading module 44, forming a bridge channel in the two directions of the loading cylinder extension and retraction, so that the loading cylinder can flexibly follow the movement of the tested electro-hydraulic servo element under the active traction of the tested electro-hydraulic servo element. The loading cylinder realizes pressure adjustment through the loading relief valve 32, and the dynamically changing pressure provides different sizes of loads for the tested electro-hydraulic servo element, thereby meeting the diverse requirements for the loading conditions of the tested element 15 during the test.

[0065] In the hydraulic test system of the electro-hydraulic servo element provided in this embodiment, the oil supply unit 43 is arranged on the base 46, including a first oil inlet filter arranged in parallel, a first oil pump motor 4 arranged in parallel, a second one-way valve 5 and a first pressure line filter 7 arranged in parallel, and the first oil inlet filter, the first oil pump motor 4, the second one-way valve 5 and the pressure line filter are connected in sequence.

[0066] In this embodiment, the oil pump is a volumetric pump, and a quantitative gear pump, a vane pump or a variable displacement piston pump may be selected. The output flow rate is adjusted by adjusting the variable mechanism of the variable displacement piston pump. The oil inlet of the first oil pump motor 4 is connected to the oil tank assembly 1, and the oil outlet of the first oil pump motor 4 is connected to the hydraulic module 40 through a pipe joint. A pipe joint is provided at the oil inlet of the hydraulic module 40, and the oil outlet is connected to the connection flange of the test element 15 on the stand 45 through a steel pipe.

[0067] In the hydraulic test system of the electro-hydraulic servo element provided in this embodiment, the oil replenishing unit 41 is arranged on the base 46, including an oil inlet filter, a second oil pump motor, a third one-way valve 31 and a second pressure line filter 30 connected in sequence, and the second oil pump motor is connected to the oil tank assembly 1; the outlet of the second oil pump motor is connected to the valve module, the valve module includes a loading overflow valve 32, an electromagnetic reversing valve 27, a second stop valve, and a second pressure gauge 28, the outlet of the loading overflow valve 32 is connected to the oil tank, one way of the oil circuit outlet of the valve module is connected to the working oil port of the electromagnetic reversing valve 27, and the other way of the oil circuit outlet of the valve module is connected to the outlet of the second stop valve.

[0068] In the hydraulic test system of the electro-hydraulic servo element provided in this embodiment, an accumulator 3 is provided at the outlet of the oil supply module, and the accumulator 3 group is arranged on the base 46. The accumulator 3 is also connected to the hydraulic module 40, and is used to maintain a constant oil supply pressure when the oil supply module switches the oil supply source, provide a supplement to the instantaneous flow demand, and smooth the pressure pulsation.

[0069] In the hydraulic test system of the electro-hydraulic servo element provided in this embodiment, the hydraulic module 40 also includes a pressure relay 12, a third pressure gauge 10 and a damper. The pressure relay 12 is used to detect the pressure threshold of the hydraulic test system. When the pressure of the hydraulic test system reaches the set high pressure threshold, the micro switch of the pressure relay 12 is energized, and the pressure relay 12 sends the micro switch energization signal to the main control module 42, and the main control module 42 controls the oil pump motor to stop. When the pressure of the hydraulic test system suddenly drops and reaches the set low pressure threshold, the pressure relay 12 outputs a signal to the main control module 42, and the main control module 42 controls the switching between the oil pump motor groups. The damping is used to smooth out the pressure pulse impact in the hydraulic module 40.

[0070] In this embodiment, during the operation of the hydraulic test system, the pressure relay 12 is used to detect the pressure threshold in the system in real time. When the pressure of the hydraulic test system reaches the set high pressure threshold, the micro switch of the pressure relay 12 is triggered and closes, and sends its detection signal to the control unit of the main control module 42. The control unit controls the motor oil pump to stop according to the signal instruction, thereby ensuring that the hydraulic test system will not be damaged due to overpressure during operation, and playing a role in system protection.

[0071] When the pressure of the hydraulic test system suddenly drops to the set low-pressure threshold, the pressure relay 12 outputs a signal to the main control module 42. After receiving the signal, the main control module 42 instructs the switching of the operating state of the motor oil pump group and activates the standby motor oil pump to supplement the pressure, thereby maintaining the stability of the working pressure of the hydraulic test system and ensuring the continuity and reliability of the test process. In addition, the hydraulic module 40 effectively smoothes the pressure shocks and fluctuations in the system by setting a damping device, further improving the stability of the operation of the hydraulic test system. The function of the damping device enables the system to maintain stable pressure under dynamic conditions, ensuring the accuracy of the test data and the safety of the equipment.

[0072] In the hydraulic test system of the electro-hydraulic servo element provided in this embodiment, the oil tank assembly 1 includes an oil tank body, a flow meter 25, a fourth one-way valve 26, a cooler 35, a temperature relay 37, an electromagnetic water valve 34 and an oil return filter 29;

[0073] The temperature relay 37 is arranged outside the oil tank body and is used to detect the temperature of the oil tank body. The cooler 35 is arranged on the top surface of the oil tank body. The inlet of the cooler 35 is connected to the oil return port of the hydraulic module 40. The outlet of the cooler 35 is connected to the flow meter 25 and the fourth one-way valve 26 in sequence. The electromagnetic water valve 34 is used to control the on-off of the external water supply pump to supply water to the cooler 35.

[0074] A liquid level control relay 38 is also provided in the oil tank body for detecting the oil height in the oil tank body. An air filter is also provided in the oil tank body for maintaining the balance between the oil tank body and the atmospheric pressure and filtering the air entering the oil tank body. In this embodiment, the liquid level control relay 38 includes two floats, which respectively set the upper and lower liquid levels. When the liquid level reaches the lower limit, the liquid level control relay 38 sends a signal to the main control module 42 to control the oil supply equipment outside the hydraulic test system to replenish the hydraulic oil to the oil tank; when the liquid level reaches the upper limit, the liquid level control relay 38 sends a signal to the main control module 42 to turn off the oil supply equipment to prevent the oil tank from being overfilled. An air filter 39 is provided on the top of the oil tank, which has both the function of a respirator and a refueling filter. The air filter 39 filters the air entering the oil tank, isolates external dust and particulate matter, and keeps the oil clean. When the oil level in the oil tank rises, the air filter 39 discharges air to the outside; when the oil level drops, it inhales external air to maintain the pressure balance inside and outside the oil tank and prevent cavitation.

[0075] Before the hydraulic test system starts running, the external water supply pump motor is started to allow the external water supply to enter the cooler 35 to form a water cycle to cool the hydraulic oil in the oil tank. Under normal circumstances, the electromagnetic water valve 34 is in a disconnected state, and the temperature relay 37 detects the temperature of the oil tank in real time. When the temperature of the oil tank exceeds the set high temperature threshold, the high temperature contact of the temperature relay 37 is connected, and the temperature relay 37 sends a signal to the main control module 42. The main control module 42 opens the electromagnetic water valve 34 through the control relay, controls the external water supply pump to start the water supply to cool the oil tank. When the temperature is lower than the set low temperature threshold, the low temperature contact of the temperature relay 37 is connected, and the main control module 42 closes the electromagnetic water valve 34 to stop the cooling cycle. The inlet of the cooler 35 is connected to the oil return port of the hydraulic module 40, and the outlet is connected to the flow meter 25 and the fourth one-way valve 26 in sequence. The flow meter 25 measures the return oil flow and uploads it to the measurement and control system. The fourth one-way valve 26 is used to branch the return oil and play a back pressure role to ensure the stability of the return oil pressure.

[0076] In the hydraulic test system of the electro-hydraulic servo element provided in the present embodiment, a pressure differential transmitter is provided in the first pressure line filter 7, the second pressure line filter 30 and the return oil filter 29, and the pressure differential transmitter is used to detect the blockage of the first pressure line filter 7, the second pressure line filter 30 and the return oil filter 29, and to warn the main control module 42. When the filter element is blocked and the pressure difference reaches the set value, the blockage contact of the pressure differential transmitter is connected and the signal is sent to the main control module 42, and the main control module 42 sends an alarm signal to prompt the staff to replace the filter element to ensure the cleanliness of the system oil.

[0077] An embodiment of the present invention further provides a hydraulic test method for an electro-hydraulic servo component, including the above-mentioned hydraulic test system for an electro-hydraulic servo component, and also includes the following experimental process:

[0078] Setting of the test element 15: The test element 15 and the loading cylinder are set at the upper and lower ends of the stand 45, the follower differential cylinder piston rod of the test element 15 is connected with the piston rod of the loading cylinder, and a tension pressure sensor 17 and a follower piston displacement sensor 18 are set between the follower differential cylinder piston rod of the test element 15 and the piston rod of the loading cylinder, and the valve core position sensor 19 is set on the control valve core of the test element 15;

[0079] Input of control signals: The control unit of the main control module 42 sends control signals to the hydraulic module 40, the power module and the tested element 15;

[0080] Oil supply and loading of the test element 15: The hydraulic oil in the oil tank is delivered to the P port of the electro-hydraulic reversing valve 9 through the first motor oil pump group in the oil supply unit 43. After the electro-hydraulic reversing valve 9 is switched to the working left position by power, the valve position remains unchanged. The hydraulic oil flows out from the A port of the electro-hydraulic reversing valve 9, passes through the first oil inlet filter and the throttle valve 14, and enters the upper and lower chambers of the follower piston of the test element 15. The main control module 42 controls the up and down movement of the follower piston of the test element 15 and the hydraulic oil pressure difference by adjusting the magnitude and direction of the input current;

[0081] When the input current of the control unit gradually increases, the pressure of the variable throttle port on the follower piston increases, and the hydraulic oil pushes the follower piston to move downward. The hydraulic oil flows through the T port of the electro-hydraulic reversing valve 9, the back pressure valve 8, the flow meter 25, the one-way valve and the filter, and finally flows back to the oil tank;

[0082] When the input current gradually decreases to zero, the follower piston of the test element 15 stops moving and maintains the current position; at this time, the flow of hydraulic oil is balanced through the power source, the electro-hydraulic reversing valve 9, the back pressure valve 8 and the throttle valve 14 to keep the pressure constant;

[0083] When the input current increases in the reverse direction, the pressure of the variable throttle port under the follower piston of the test element 15 increases, and the hydraulic oil pushes the follower piston to move upward. The hydraulic oil flows through the T port of the electro-hydraulic reversing valve 9, the back pressure valve 8, the flow meter 25, the one-way valve and the filter, and finally flows back to the oil tank;

[0084] Oil replenishment and loading of the loading cylinder: the hydraulic oil in the oil tank is transported to the P port of the electromagnetic reversing valve 27 of the loading module 44 through the second motor oil pump group in the loading oil replenishment power module. After the electromagnetic reversing valve 27 is energized and in the left position, the valve position remains unchanged, so that the hydraulic oil flows out from the A port of the electromagnetic reversing valve 27, passes through the loading overflow valve 32 and the one-way valve bridge channel in the loading module 44, and the replenishing oil enters the forward volume of the loading cylinder. The piston rod of the loading cylinder moves outward under the drag of the tested electro-hydraulic servo element; at the same time, the hydraulic oil in the backward volume of the loading cylinder is squeezed and flows back to the oil tank through the one-way valve and the loading overflow valve 32;

[0085] During the oil replenishment and loading process, the oil supply pressure of the loading cylinder is set unchanged by the power module overflow valve, and the loading overflow valve 32 adjusts the loading pressure of the loading cylinder in real time until the loading pressure reaches the load pressure value required by the test; the main control module 42 monitors the loading pressure value through the control unit, and when the tested electro-hydraulic servo element reaches the specified position or the adjusted loading pressure exceeds the actual required value, the loading cylinder stops moving;

[0086] Collection and processing of test element 15 parameters: The collection unit of the main control module 42 collects the load force signal, piston displacement signal and valve core position signal fed back by the tension and pressure sensor 17, the follower piston displacement sensor 18 and the valve core position sensor 19 in real time. The processing unit generates various characteristic curves of the test element 15 according to the load force parameters, valve core position parameters, piston displacement parameters of the test element 15 and the flow parameters obtained according to the piston displacement parameters.

[0087] In this embodiment, when the no-load related test is performed on the test element 15, the fourth stop valve J4, the seventh stop valve J7, and the third stop valve J3 are first opened, the first stop valve J1 and the eighth stop valve J8 are closed, the connection between the loading cylinder and the test element 15 is disconnected, and the electro-hydraulic reversing valve 9 is powered and switched to the working left position, so that the high pressure of the pressure oil reaches the variable throttle port on the follower piston of the test electro-hydraulic servo element through the filter and the throttle valve 14, and the pressure oil flows back to the oil tank from the variable throttle port under the follower piston through the T port of the electro-hydraulic reversing valve 9, the back pressure valve 8, the flow meter 25, the one-way valve, the filter, and the cooler 35.

[0088] When the load-related test is performed on the test element 15, the fourth stop valve J4, the seventh stop valve J7, the third stop valve J3, the sixth stop valve J6, the second stop valve J2, and the ninth stop valve J9 are first opened, and the first stop valve J1, the eighth stop valve J8, the tenth stop valve J10, and the eleventh stop valve J11 are closed. The oil in the oil tank is sequentially delivered to the P port of the electromagnetic reversing valve 27 through the second oil pump motor unit 33, the third check valve 31, and the second pressure line filter 30 of the oil replenishment unit 41, and the loading relief valve 32 in the valve module is adjusted until the pressure oil in the valve module reaches the oil replenishment control pressure. The electromagnetic reversing valve 27 is energized and switched to the working left position, so that the pressure oil reaches the front end of the paired connected check valve of the second integrated block in the loading module 44, and then enters the forward volume enlargement chamber of the loading oil cylinder through the check valve bridge channel to squeeze out the oil in the volume shrinkage chamber of the loading oil cylinder, and the squeezed oil flows back to the oil tank through the loading relief valve 32.

[0089] Or first open the fourth stop valve J4, the seventh stop valve J7, the third stop valve J3, and the eighth stop valve J8, and close the ninth stop valve J9, the tenth stop valve J10, and the eleventh stop valve J11, and adjust the loading overflow valve 32 and the safety valve 24 in the valve module to the oil supply pressure. The branch of the pressure oil output by the oil supply unit 43 in the power module reaches the front end of the paired one-way valve of the second integrated block in the loading module 44, and then passes through the one-way valve bridge channel to replenish the forward volume enlargement chamber of the loading cylinder, squeeze out the oil in the volume shrinkage chamber of the loading cylinder, and the squeezed oil flows back to the oil tank through the loading overflow valve 32.

[0090] Specifically in this embodiment, the test on the test element 15 includes the following contents:

[0091] No-load displacement (flow) characteristic test: When the load pressure difference ΔpL is 0 and the oil supply pressure ps is a constant, the main control module 42 inputs a current i that changes according to a working cycle (i.e., from 0→imax+→0→imax-→0), and correspondingly collects the displacement s change of the follower piston of the test element 15, and indirectly obtains the change of the output flow q of the test element 15. The obtained curve is the no-load displacement (flow) characteristic of the test element 15, wherein the flow is collected by the follower piston displacement sensor 18, and the data change of the flowmeter 25 is observed at the same time.

[0092] Displacement (flow) characteristic test under load: The main control module 42 keeps the input current i as a constant, and controls the load pressure difference ΔpL to change from 0 to ps (load force f), and collects the displacement s (i.e., the output flow q of the test element 15) value of the corresponding follower piston of the test element 15 within this range. The main control module 42 changes the input current i to different constants, and the obtained curve is the load displacement (flow) characteristic curve.

[0093] Throttling characteristic test: When the oil supply pressure ps is constant, the main control module 42 inputs a current i that changes according to a working cycle (i.e., from 0→imax+→0→imax-→0), and the corresponding output displacement is collected. The resulting curve is the throttling characteristic curve.

[0094] Zero-consumption flow: When the oil supply pressure ps of the test element 15 is constant, the main control module 42 inputs current i, the collection unit collects the flow qr flowing out of its leakage oil port, and the processing unit draws a zero-consumption flow-current curve.

[0095] Oil supply pressure zero drift: When the load pressure difference ΔpL is 0 and the oil supply pressure ps is constant, the main control unit inputs a triangular wave current and obtains the flow rate q near the zero position of the test element 15 (obtained by the displacement s of the follower piston), which is the zero deviation. According to the change of the oil supply pressure ps, the characteristic curve of the zero deviation with the oil supply pressure is obtained. The ratio of 60% to 100% of the oil supply pressure zero deviation is found from the curve and expressed as a percentage.

[0096] Load zero drift: When the load pressure difference ΔpL is 0 and the oil supply pressure ps is constant, the main control unit inputs a triangular wave current to obtain the flow q (displacement s) near the zero position of the test element 15, that is, the zero offset. According to the change of the oil supply pressure ps, the characteristic curve of the zero offset changing with the load (psA) is obtained. The value of the load zero offset when the oil supply pressure is 60% to 100% is found from the curve and expressed in length unit mm.

[0097] Frequency dynamic characteristic test: the main control module 42 inputs a current that changes sinusoidally within a certain frequency range, and collects the complex ratio of the no-load flow of the valve of the test element 15 to the input current, which is the frequency characteristic of the test element 15.

[0098] Power module switching pressure change: When switching from one oil supply power source to another, first start the other oil supply power source so that both sources are supplied with oil at the same time, and then stop the original oil supply power source, so that the oil supply pressure ps and the load pressure difference ΔpL are constant.

[0099] Resilience: The oil supply pressure ps is a constant, the main control module 42 inputs a current i that changes according to a working cycle (i.e., from 0→imax+→0→imax-→0), switches the valve position of the electro-hydraulic reversing valve 9 to the non-working position, i.e., the right position, and the follower piston of the test element 15 moves to the bottom of the full stroke.

[0100] This embodiment can directly collect the displacement signal of the valve core by setting the valve core position sensor 19 on the follower differential cylinder control valve core of the test element 15, and form an accurate correspondence with the input current of the main control module 42. This direct position feedback method avoids the error accumulation of the traditional indirect derivation of the valve core position through flow or pressure, realizes high-precision measurement of dynamic response characteristics and zero-consumption flow, and provides a reliable basis for evaluating the dynamic performance of the test element 15.

[0101] At the same time, this embodiment adopts an open-loop test method, through the precise control of the hydraulic module 40 and the power module by the main control module 42, the dynamic adjustment of the valve core position, flow and pressure is achieved by adjusting the input current, avoiding the feedback signal interference problem in the closed-loop test. The control lag and oscillation phenomenon commonly seen in closed-loop tests are effectively eliminated, thereby ensuring the authenticity and stability of the test data, especially in the throttling characteristic test, the oil supply pressure zero drift test and other tests.

[0102] In the load-related test, the loading module 44 adjusts the loading pressure of the loading cylinder in real time through the overflow valve, and moves in conjunction with the test element 15 to provide dynamic load support. The dynamic loading capability of the loading cylinder avoids the problem of error accumulation in traditional closed-loop regulation, ensuring high precision of the load displacement (flow) characteristic test. At the same time, the oil supply pressure is strictly controlled to be constant during the oil replenishment and loading process of the loading cylinder, making the load pressure regulation process smoother and providing reliable support for dynamic characteristic tests.

[0103] The main control module 42 realizes real-time acquisition and analysis of multiple parameters such as valve core position, load force, piston displacement and flow rate through the acquisition unit and the processing unit, and generates multiple test curves including no-load displacement (flow rate) characteristics, loaded displacement (flow rate) characteristics, zero-consumption flow rate and frequency dynamic characteristics. This synchronous acquisition method of multi-dimensional parameters makes the test data more comprehensive and can clearly reflect the dynamic performance and comprehensive characteristics of the tested component 15.

[0104] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A hydraulic test system for an electro-hydraulic servo component, comprising a frame and an oil tank assembly (1), a power module, a hydraulic module (40), a loading module (44), a feedback module and a main control module (42) arranged on the frame, characterized in that: The frame comprises a base (46) and a stand (45); The hydraulic module (40) is arranged on the base (46), and comprises a first integrated block, and a first overflow valve (23), a safety valve (24), a flow valve (6), a first stop valve, an electro-hydraulic reversing valve (9), a throttle valve (14), and a back pressure valve (8) arranged on the first integrated block. The first overflow valve (23), the safety valve (24), the flow valve (6), the first stop valve, the electro-hydraulic reversing valve (9), the throttle valve (14), and the back pressure valve (8) are connected via a flow channel arranged in the first integrated block. The hydraulic module (40) is used to control the pressure change of the hydraulic source and the movement of the valve core of the driving pressure regulating valve of the test element (15), and is also used to provide back pressure for the test element (15); The loading module (44) is arranged on the base (46), and comprises a second integrated block and a loading oil cylinder, and four first one-way valves (21), a second overflow valve (22), and a first pressure gauge (20) arranged on the second integrated block; the four first one-way valves (21), the second overflow valve (22), the first pressure gauge (20), and the loading oil cylinder are connected via a flow channel arranged in the second integrated block, and the loading module (44) is connected to the power module; the four one-way valves form a bridge channel in two directions of extension and retraction of the loading oil cylinder, and provide a loading and oil replenishing channel for the loading oil cylinder; The power module comprises an oil supply unit (43) for supplying oil to the test element (15) and an oil replenishment unit (41) for replenishing oil to the loading cylinder, the oil supply unit (43) and the oil replenishment unit (41) are respectively connected to the oil tank assembly (1) to draw oil from the oil tank assembly (1), and the hydraulic module (40) and the power module are also used to provide a constant pressure dynamically switched parallel hydraulic source for the test element (15); The test element (15) and the loading cylinder are arranged on the stand (45); the feedback module is arranged between the piston rod of the follower differential cylinder of the test element (15) and the piston rod of the loading cylinder; the feedback module comprises a tension pressure sensor (17), a follower piston displacement sensor (18) and a valve core position sensor (19); the valve core position sensor (19) is arranged on the valve core of the follower differential cylinder of the test element (15); The main control module (42) comprises a control unit connected to the power module and the hydraulic module (40), a collection unit and a processing unit connected to the tension and pressure sensor (17), the follower piston displacement sensor (18) and the valve core position sensor (19), wherein the control unit is used to control the power module and the hydraulic module (40), and the collection unit and the processing unit are used to collect and process the valve core position, force, displacement and flow data of the test element (15).

2. The electro-hydraulic servo component hydraulic test system according to claim 1, characterized in that: The first overflow valve (23), the safety valve (24), the flow valve (6), and one end valve port of the first stop valve are connected in parallel and are respectively connected to the P port of the electro-hydraulic reversing valve (9) and the interface of the first integrated block connected to the loading module (44); The first overflow valve (23), the safety valve (24), the flow valve (6), and the other end valve ports of the stop valve are connected to the interface of the first integrated block connected to the oil tank assembly (1); The T port of the electro-hydraulic reversing valve (9) is connected to the inlet of the back pressure valve (8), the A port of the electro-hydraulic reversing valve (9) is also connected to a high-pressure filter (13), and is connected to a pressure valve port of a test element (15) through the high-pressure filter (13) and the throttle valve (14), and the B port of the electro-hydraulic reversing valve (9) is connected to another pressure valve port of the test electro-hydraulic servo element through the first integrated block; The outlet of the back pressure valve (8) on the first integrated block is connected to the oil tank assembly (1).

3. The electro-hydraulic servo component hydraulic test system according to claim 1, characterized in that: The four first one-way valves (21) are connected in pairs in sequence through the flow passage inside the second integrated block; the first ends of the first one-way valves (21) connected in pairs are connected to the interface of the second integrated block connected to the hydraulic module (40); the second ends of the first one-way valves (21) connected in pairs are connected to the second overflow valve (22) and the first pressure gauge (20); the third ends and the fourth ends of the first one-way valves (21) connected in pairs are respectively connected to the interfaces of the second integrated block connected to the two oil ports of the loading cylinder; The outlet of the second overflow valve (22) on the second integrated block is connected to the oil tank assembly (1).

4. The electro-hydraulic servo component hydraulic test system according to claim 1, characterized in that: The oil supply unit (43) is arranged on the base (46), and comprises a first oil inlet filter, a first oil pump motor (4) arranged in parallel, a second one-way valve (5) and a first pressure line filter (7) arranged in parallel, wherein the first oil inlet filter, the first oil pump motor (4), the second one-way valve (5) and the pressure line filter are connected in sequence.

5. The electro-hydraulic servo component hydraulic test system according to claim 4, characterized in that: The oil replenishment unit (41) is arranged on the base (46), and comprises a second oil inlet filter, a second oil pump motor, a third non-return valve (31) and a second pressure line filter (30) which are connected in sequence, and the second oil pump motor is connected to the oil tank assembly (1); the outlet of the second oil pump motor is connected to a valve module, and the valve module comprises a loading overflow valve (32), an electromagnetic reversing valve (27), a second stop valve, and a second pressure gauge (28); the outlet of the loading overflow valve (32) is connected to the oil tank, one of the oil outlets of the valve module is connected to the working oil port of the electromagnetic reversing valve (27), and the other of the oil outlets of the valve module is connected to the outlet of the second stop valve.

6. The electro-hydraulic servo component hydraulic test system according to claim 5, characterized in that: An accumulator (3) is provided at the outlet of the oil supply module. The accumulator (3) group is arranged on the base (46). The accumulator (3) is also connected to the hydraulic module (40) and is used to maintain a constant oil supply pressure when the oil supply module switches the oil supply source, supplement the instantaneous flow demand, and smooth the pressure pulsation.

7. The electro-hydraulic servo component hydraulic test system according to claim 6, characterized in that: The hydraulic module (40) further comprises a pressure relay (12), a third pressure gauge (10) and a damper. The pressure relay (12) is used to detect a pressure threshold of a hydraulic test system. When the pressure of the hydraulic test system reaches a set high pressure threshold, the micro switch of the pressure relay (12) is energized. The main control module (42) obtains a signal indicating that the pressure relay (12) has energized the micro switch, and controls the first oil pump motor (4) or the second oil pump motor to stop. When the pressure of the hydraulic test system drops to a set low pressure threshold, the main control module (42) controls the switching between the oil pump motor groups. The damper is used to smooth the pressure pulse shock in the hydraulic module (40).

8. The electro-hydraulic servo component hydraulic test system according to claim 6, characterized in that: The oil tank assembly (1) comprises an oil tank body, a flow meter (25), a fourth one-way valve (26), a cooler (35), a temperature relay (37), an electromagnetic water valve (34) and an oil return filter (29); The temperature relay (37) is arranged outside the oil tank body and is used to detect the temperature of the oil tank body. The cooler (35) is arranged on the top surface of the oil tank body. The inlet of the cooler (35) is connected to the oil return port of the hydraulic module (40), and the outlet of the cooler (35) is connected to the flow meter (25) and the fourth one-way valve (26) in sequence; the electromagnetic water valve (34) is used to control the on and off of the water supply from the external water supply pump to the cooler (35); The oil tank body is also provided with a liquid level control relay (38) for detecting the oil height in the oil tank body. The oil tank body is also provided with an air filter for maintaining the balance between the oil tank body and the atmospheric pressure and filtering the air entering the oil tank body.

9. The electro-hydraulic servo component hydraulic test system according to claim 8, characterized in that: The first pressure line filter (7), the second pressure line filter (30) and the return oil filter (29) are provided with a pressure differential transmitter, which is used to detect the blockage of the first pressure line filter (7), the second pressure line filter (30) and the return oil filter (29) and to give an alarm to the main control module (42).

10. A hydraulic test method for an electro-hydraulic servo component, characterized in that: The electro-hydraulic servo component hydraulic test system according to any one of claims 1 to 9 further comprises the following experimental process: Setting of the test element (15): the test element (15) and the loading cylinder are set at the upper and lower ends of the stand (45), the follower differential cylinder piston rod of the test element (15) is connected with the piston rod of the loading cylinder, and a tension pressure sensor (17) and a follower piston displacement sensor (18) are set between the follower differential cylinder piston rod of the test element (15) and the piston rod of the loading cylinder, and the valve core position sensor (19) is set on the control valve core of the test element (15); Input of control signals: the control unit of the main control module (42) sends control signals to the hydraulic module (40), the power module and the tested element (15); Oil supply and loading of the test element (15): the hydraulic oil in the oil tank is transported to the P port of the electro-hydraulic reversing valve (9) through the first motor oil pump group in the oil supply unit (43); the electro-hydraulic reversing valve (9) maintains the valve position unchanged after being energized to switch the electro-hydraulic reversing valve (9) to the working left position; the hydraulic oil flows out from the A port of the electro-hydraulic reversing valve (9), passes through the first oil inlet filter and the throttle valve (14), and enters the upper and lower chambers of the follower piston of the test element (15); the upper and lower movement of the follower piston of the test element (15) and the hydraulic oil pressure difference are controlled by adjusting the magnitude and direction of the input current; When the input current of the control unit gradually increases, the pressure of the variable throttle port on the follower piston increases, and the hydraulic oil pushes the follower piston to move downward. The hydraulic oil flows through the T port of the electro-hydraulic reversing valve (9), the back pressure valve (8), the flow meter (25), the check valve and the filter, and finally flows back to the oil tank; When the input current gradually decreases to zero, the follower piston stops moving and maintains the current position; at this time, the flow of hydraulic oil is balanced through the oil circuit of the power source, the electro-hydraulic reversing valve (9), the back pressure valve (8) and the throttle valve (14) to maintain a constant pressure; When the input current increases in the reverse direction, the pressure at the variable throttle port under the follower piston increases, and the hydraulic oil pushes the follower piston upward. The hydraulic oil flows through the T port of the electro-hydraulic reversing valve (9), the back pressure valve (8), the flow meter (25), the check valve and the filter, and finally flows back to the oil tank. Oil replenishment and loading of the loading oil cylinder: the hydraulic oil in the oil tank is transported to the P port of the electromagnetic reversing valve (27) of the loading module (44) through the second motor oil pump group in the loading oil replenishment power module. After the electromagnetic reversing valve (27) is energized and in the left position, the valve position remains unchanged, so that the hydraulic oil flows out from the A port of the electromagnetic reversing valve (27), passes through the loading overflow valve (32) and the one-way valve bridge channel in the loading module (44), and the replenishing oil enters the forward volume of the loading oil cylinder. The piston rod of the loading oil cylinder moves outward under the drag of the tested electro-hydraulic servo element; at the same time, the hydraulic oil in the backward volume of the loading oil cylinder is squeezed and flows back to the oil tank through the one-way valve and the loading overflow valve (32); During the oil replenishment and loading process, the oil supply pressure of the loading cylinder is set unchanged by the overflow valve of the power module, and the loading overflow valve (32) adjusts the loading pressure of the loading cylinder in real time until the loading pressure reaches the load pressure value required by the test; the main control module (42) monitors the loading pressure value through the control unit, and when the tested electro-hydraulic servo element reaches the specified position or the adjusted loading pressure exceeds the actual required value, the loading cylinder stops moving; Collection and processing of test element (15) parameters: The collection unit of the main control module (42) collects in real time the load force signal, piston displacement signal and valve core position signal fed back by the tension and pressure sensor (17), the follower piston displacement sensor (18) and the valve core position sensor (19); the processing unit generates various characteristic curves of the test element (15) based on the load force parameter, valve core position parameter, piston displacement parameter and flow parameter obtained based on the piston displacement parameter of the test element (15).

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