Simulation test device and comprehensive test platform for oil stirring flow characteristics in compact cavity of servo motor pump

Abstract

The present invention discloses a simulated test device for the oil-stirring flow characteristics of a compact cavity of a servo motor pump and a comprehensive test platform thereof. A simulated test device for the oil-stirring flow characteristics of a compact cavity that takes leakage flow regulation into consideration is designed. By adjusting the gap size between the leakage oil port and the baffle, the effect of leakage flow on the oil-stirring flow characteristics under different working conditions can be realistically simulated, thereby achieving an accurate evaluation of the oil-stirring flow characteristics. At the same time, tracer particles are used to simulate the wear debris contamination particles generated by the servo motor pump during actual operation. Combined with a laser source and a high-speed camera, the flow characteristics of the oil-stirring flow field and the visualization of the distribution of pollutant deposition can be achieved. The present invention provides an important experimental basis for studying the oil-stirring flow characteristics of the integrated motor pump rotor in a compact cavity and for visually observing the deposition flow state of wear debris contaminants.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic pumps, and in particular relates to a simulated testing device for oil stirring flow characteristics of a compact cavity of a servo motor pump and a comprehensive testing platform thereof. Background Art

[0002] As a key component of electro-hydraulic actuators (EHAs), servo motor pumps serve as both pumps and motors, combining multiple functions such as power output, energy conversion, and precise control. They are widely used in aerospace, medical equipment, industrial robotics, and other fields. As a new integrated product, servo motor pumps eliminate the traditional dynamic seal between the motor and pump shafts. Instead, all internal motor components, including the stator, rotor, windings, and main shaft, are completely immersed in oil. As high-pressure oil leaks through the friction gap of the plunger pump, it churns at high speed within the motor pump housing and flows through the motor to cool the stator and rotor. This "coaxial, co-housing, and co-flow" structure not only improves seal reliability but also enhances the servo motor pump's heat dissipation efficiency. However, the servo motor pump rotor's churning of the oil generates additional friction losses, causing turbulence and eddy currents within the integrated housing, which directly impacts the servo motor pump's performance. Therefore, studying the flow characteristics of the oil churn within the compact housing of the integrated motor pump rotor is crucial for improving the efficiency and extending the service life of the servo motor pump.

[0003] While there are existing testing devices for the oil stirring characteristics of standalone axial piston pumps, few are designed to test the flow characteristics of integrated cavities like motor pumps. Compared to traditional piston pumps, testing the flow characteristics of integrated cavities in servo motor pumps presents the following difficulties: 1. Accurate simulation of pump leakage: To avoid the "burning" phenomenon that can occur when testing oil stirring in dry housings, existing testing devices typically remove the pump's friction pair. This design only simulates the circumferential stirring of the oil within the housing cavity, but fails to accurately simulate the axial flow characteristics of the leaking oil, resulting in significant limitations in the test results. 2. Traditional piston pumps are equipped with filters to ensure circuit contamination levels. However, servo motor pumps have coaxial pump and motor flow fields. Wear debris carried in the leaking oil can be affected by electromagnetic forces and become entrained in the motor's air gap, potentially scratching the stator core, blocking cooling channels, or even causing motor failure. Therefore, visual observation of the deposition and flow of wear debris is crucial for ensuring the reliable operation of servo motor pumps. Summary of the Invention

[0004] The purpose of the present invention is to address the deficiencies of the existing technology and provide a simulated test device and a comprehensive test platform for the oil stirring flow characteristics of a servo motor pump in a compact cavity, which provides an important experimental basis for studying the oil stirring flow characteristics of the integrated motor pump rotor in a compact cavity and visually observing the deposition flow state of wear debris contaminants.

[0005] The object of the present invention is achieved through the following technical solutions: a simulated test device for the oil stirring flow characteristics of a compact cavity of a servo motor pump, the device comprising an oil-through end cover, an oil-through shaft and a simulated pump body rotating assembly;

[0006] The oil-passing end cover is connected to the oil-passing shaft, and the pressurized oil in the oil-passing end cover enters the interior of the simulated test device through the rotating oil-passing shaft;

[0007] The oil-passing shaft is solidified with the cylinder body and rotates with the main shaft. The pressurized oil is divided into three parts after passing through the flow channel in the cylinder body: one part flows out from the plunger auxiliary nozzle flow channel and shoots toward the tapered end face of the plunger slipper assembly to simulate plunger auxiliary leakage; one part flows out from the distribution auxiliary nozzle flow channel and shoots toward the distribution auxiliary leakage regulating baffle to simulate distribution auxiliary leakage; and one part flows out from the slipper auxiliary nozzle flow channel and shoots toward the slipper auxiliary leakage regulating baffle to simulate slipper auxiliary leakage.

[0008] The simulated pump body rotating assembly includes a cylinder body, a plunger shoe and a swash plate. The cylinder body is rigidly fastened to the main shaft and a gap is left between the cylinder body and the end face of the pump housing. The plunger and the shoe are designed as an integrated structure.

[0009] Furthermore, the distribution pair leakage regulating baffle cylinder body, the slipper pair leakage regulating baffle and the slipper of the plunger slipper assembly, the plunger of the plunger slipper assembly and the corresponding cylinder hole are connected through fine thread.

[0010] Furthermore, the method for adjusting the leakage flow of the plunger pair, the distribution pair and the slipper pair is: by adjusting the gap between the end face of the plunger slipper assembly and the end face of the cylinder threaded hole, the gap between the plunger slipper assembly and the slipper pair leakage adjustment baffle, and the gap between the cylinder body and the distribution pair leakage adjustment baffle, and utilizing the self-locking property of the fine thread, changing the number of turns of the thread rotation to accurately adjust the distance between the baffle and the end face, thereby adjusting the leakage flow of the plunger pair, the distribution pair and the slipper pair.

[0011] Furthermore, the motor pump main shaft is rigidly connected to the cylinder body and the motor rotor, and the plunger shoe assemblies are respectively fastened in the corresponding cylinder holes. The overhanging length of each plunger shoe assembly remains consistent and a certain gap is retained with the swash plate fixed on the connecting flange.

[0012] On the other hand, the present invention also provides a comprehensive testing platform for a simulated testing device based on the oil stirring flow characteristics of a servo motor pump compact cavity, which includes: a simulated testing device, an oil supply pump, an oil tank, a contaminant tracer particle cavity, a high-speed camera, and a data acquisition and control system;

[0013] The oil supply pump is connected to the drive motor, and the pressure is regulated by the loading relief valve, and the oil is supplied to the simulated test device through the gear flowmeter and the one-way valve. The pollutant tracer particle chamber is connected to the main oil circuit through the butterfly valve, and the tracer particles enter the simulated test device along with the pressurized oil through the rotating oil shaft.

[0014] The leaked oil of the simulated test device is discharged from the leakage oil port, and then returns to the oil tank after passing through a one-way valve, a gear flow meter, and a filter; the simulated test device is connected to a high-speed drive motor through a speed and torque sensor;

[0015] The high-speed camera is facing the simulated test device;

[0016] The data acquisition and control system is used to collect pressure signals, temperature signals, flow signals, speed signals, torque signals and visual flow field imaging information of the comprehensive test platform, and to regulate the drive motor, high-speed drive motor and loading overflow valve of the oil supply pump.

[0017] Furthermore, the loading relief valve is adjusted to the set pressure, the driving motor speed is adjusted to the set speed, the driving torque under the current working conditions is measured through the speed torque sensor, and then the oil in the simulated test device is drained through the oil drain port, and the pressure and speed are adjusted to the same working conditions, and the torque value under the no-oil stirring condition is recorded again; finally, the data before and after are subtracted to obtain the oil stirring loss torque of the servo motor pump in the compact cavity.

[0018] Furthermore, the oil supply pump motor, loading relief valve, and high-speed drive motor are adjusted to the set working conditions; the butterfly valve is opened to release the tracer particles in the pollutant tracer particle chamber to simulate the wear debris contamination particles in the servo motor pump.

[0019] Furthermore, a high-speed camera is set in the direction perpendicular to the illuminated section, and continuously captures the behavior of the illuminated flow field at a set time interval, and transmits the data to the data acquisition and control system; finally, the data acquisition and control system processes the data to obtain the flow characteristics of the servo motor pump stirring oil flow field and pollutant deposition distribution information.

[0020] The beneficial effects of the present invention are:

[0021] 1. Innovatively, the simulation of the leakage flow of the three major friction pairs of the plunger pump is introduced into the test of the oil stirring characteristics. By adjusting the gap between the leakage oil port and the baffle, the influence of the leakage flow on the oil stirring flow characteristics under different working conditions can be realistically simulated, thereby achieving an accurate evaluation of the oil stirring flow characteristics.

[0022] 2. Innovatively use tracer particles to simulate the wear debris pollution particles generated by the servo motor pump during actual operation. Combined with laser sources, high-speed cameras and other equipment, the flow characteristics of the servo motor pump's oil stirring flow field and the visualization information of the pollutant deposition distribution are intuitively obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The overall axonometric diagram of the simulated test device for the flow characteristics of oil stirring in a compact cavity;

[0024] Figure 2 The overall cross-sectional view of the simulated test device for the flow characteristics of oil stirring in a compact cavity;

[0025] Figure 3 This is a schematic diagram of the device for regulating the leakage flow of the three major friction pairs of the present invention;

[0026] Figure 4 This is the system schematic diagram of the comprehensive test platform for the servo motor pump stirring oil flow characteristics;

[0027] Reference numerals:

[0028] 1. Oil-through end cap, 2. Seal ring, 3. Pump housing, 4. Distribution pair leakage adjustment baffle, 5. Cylinder plug, 5a. Cylinder body flow channel, 5b. Plunger auxiliary nozzle flow channel, 5c. Distribution auxiliary nozzle flow channel, 6. Plunger slipper assembly, 6a. Slipper auxiliary nozzle flow channel, 7. Slipper pair leakage adjustment baffle, 8. Support bearing, 9. Motor housing, 10. Motor stator winding, 11. Motor rotor, 12. Motor bearing, 13. Shaft end cap, 14. Leakage oil port, 15. Motor pump main shaft, 16. Connecting flange, 17. Fastener Bolts, 18. Swash plate, 19. Cylinder block, 20. Oil shaft, 21. Oil seal, 22. Pump bearing, 23. Oil pump motor, 24. Oil pump, 25. Check valve, 26. Gear flowmeter, 27. Pressure sensor, 28. Loading relief valve, 29. Filter, 30. Contaminant tracer particle chamber, 31. Butterfly valve, 32. Temperature sensor, 33. Measured servo motor pump, 34. Speed ​​and torque sensor, 35. High-speed drive motor, 36. High-speed camera, 37. Laser source, 38. Data acquisition and control system. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] like Figure 1 and Figure 2 As shown, in one embodiment, the present invention provides a simulated testing device for the flow characteristics of oil stirring in a compact cavity of a servo motor pump. The specific structure is as follows. In the axial direction, the oil-passing end cover 1, pump housing 3, connecting flange 16, motor housing 9, and shaft end cover 13 are positioned with locating pins and fastened together with bolts 17. A sealing ring 2 and an oil seal 21 seal the mating end surfaces to prevent oil leakage. The pump bearing 22, support bearing 8, and motor bearing 12 are mounted on the oil-passing end cover 1, connecting flange 16, and shaft end cover 13, respectively, to support the entire motor-pump integrated rotor. Within the motor housing 9 and pump housing 3, respectively, are simulated electromagnetic windings (including the motor stator winding 10 and motor rotor 11) and simulated pump body rotating assembly (including the cylinder 19, plunger shoe assembly 6, and swash plate 18). The main shaft 15 and motor rotor 11 are rigidly connected, and the stator winding is bolted to the motor housing 9. The main shaft 15 and the cylinder body 19 are rigidly fastened together, and a certain gap is left between the cylinder body 19 and the end face of the pump housing 3. The plunger and the slipper are designed as an integrated structure, that is, the plunger slipper assembly 6. The overhanging length of each plunger slipper assembly 6 is kept consistent and maintains a certain gap with the swash plate 18 fixed on the connecting flange. The distribution pair leakage adjustment baffle 4 is connected to the cylinder body 19 through a fine-pitch thread. The fine-pitch thread has a strong self-locking property. The distance between the end face of the distribution pair leakage adjustment baffle and the end face of the cylinder body can be accurately adjusted by changing the number of rotations of the distribution pair leakage adjustment baffle 4; the plunger of each plunger slipper assembly 6 is connected to the corresponding cylinder hole through a fine-pitch thread. The distance between the end face of the plunger slipper assembly and the end face of the cylinder hole can be accurately adjusted by changing the number of rotations of the plunger slipper assembly 6; the slipper pair leakage adjustment baffle 7 is connected to the slipper of the plunger slipper assembly 6 through a fine-pitch thread. The distance between the end face of the slipper pair leakage adjustment baffle and the end face of the slipper can be accurately adjusted by changing the number of rotations of the slipper pair leakage adjustment baffle 7.

[0031] like Figure 3As shown, the present invention innovatively incorporates the simulation of the leakage flow of the three major friction pairs of the plunger pump into the oil stirring characteristic test. This is the key to accurately evaluating the oil stirring flow characteristics. The specific implementation method is as follows. First, the pressurized oil in the oil-passing end cap 1 enters the interior of the simulated test device through the rotating oil-passing shaft 20. The oil-passing shaft 1 is fixed to the cylinder body 19 and rotates with the main shaft 15. After passing through the flow channel 5a in the cylinder body, the high-pressure oil is divided into three parts: one part flows out of the plunger auxiliary nozzle flow channel 5b and is directed to the tapered end face of the plunger slipper assembly 6 to simulate the leakage flow of the plunger pair; another part flows out of the distribution nozzle flow channel 5c and is directed to the distribution pair leakage adjustment baffle 4 to simulate the leakage flow of the distribution pair; and another part flows out of the slipper nozzle flow channel 6a and is directed to the slipper pair leakage adjustment baffle 7 to simulate the leakage flow of the slipper pair.

[0032] The gap δ1 between the end face of the plunger shoe assembly 6 and the end face of the threaded hole in the cylinder body 19 is flexibly adjusted according to different test conditions, thereby varying the injection leakage flow rate of the plunger pair. Fine threads have a strong self-locking property. Changing the number of turns of the thread precisely adjusts the distance between the baffle and the end face. The pitch directly determines the distance changed by one turn. To reduce the leakage of the friction pair, the distance the baffle moves can be appropriately reduced, reducing the gap between the two and thus reducing leakage. Conversely, to increase the leakage of the friction pair, the distance the baffle moves can be appropriately increased to increase the gap.

[0033] The calculation formula of the plunger pair leakage flow is as follows:

[0034] (1)

[0035] Where d p is the plunger diameter, δ1 is the average gap between the plunger and the plunger hole, μ is the oil viscosity, l p is the contact length between the plunger and the plunger hole, v p is the axial velocity of the plunger, ε is the average eccentricity of the plunger in the plunger hole, P c The leakage flow rate of the injection shoe pair can be changed by adjusting the gap δ2 between the plunger shoe assembly 6 and the shoe pair leakage adjustment baffle 7.

[0036] The calculation formula of the slipper pair leakage flow is as follows:

[0037] (2)

[0038] in

[0039] , , (3)

[0040] Where d pb is the diameter of the plunger damping hole, l pb is the length of the plunger damping hole, d sb is the diameter of the damping hole of the sliding shoe, l sb is the length of the damping hole of the sliding shoe, δ2 is the average gap between the sliding shoe and the swash plate, R sp r is the outer radius of the sealing band on the bottom of the sliding shoe, sp The inner radius of the sealing band on the bottom surface of the sliding shoe. By adjusting the gap δ3 between the cylinder body 19 and the distribution pair leakage adjustment baffle 4, the leakage flow rate of the distribution pair can be changed. The calculation formula of the distribution pair leakage flow rate is as follows:

[0041] (4)

[0042] Where φ0 is the wrap angle of the plunger cavity outlet, δ3 is the average gap between the cylinder end face and the distribution plate, R1 is the inner radius of the inner sealing zone of the distribution plate, R2 is the outer radius of the inner sealing zone of the distribution plate, R3 is the inner radius of the outer sealing zone of the distribution plate, and R4 is the outer radius of the outer sealing zone of the distribution plate.

[0043] Mechanical friction losses in the aforementioned device are eliminated through the following methods. The main shaft and cylinder block, as well as the main shaft and motor rotor, are rigidly fastened together. A clearance is maintained between the cylinder block 19 and the end face of the pump housing 3 to prevent friction, thereby eliminating the effects of friction between the main shaft 15 and the cylinder block 19, and between the main shaft 15 and the motor rotor 11. The plunger and shoe are designed as an integrated structure, with the plunger shoe assemblies threadedly fastened into their corresponding cylinder bores, thereby eliminating the effects of friction between the plunger and cylinder block, and between the plunger and shoe. Each plunger shoe assembly maintains a consistent extension length and maintains a clearance with the swash plate 18 fixed to the connecting flange, thereby eliminating the effects of friction between the plunger shoe 6 and the swash plate 18.

[0044] Visual observation of the churning oil flow characteristics within the compact cavity is achieved by using high-strength transparent acrylic material to process the pump housing 4 and motor housing 16, which not only meets the housing's maximum pressure resistance of 1 MPa but also allows the internal churning oil flow state to be clearly visible.

[0045] like Figure 4As shown, in one embodiment, based on the above-mentioned simulation test device, a comprehensive test platform for the compact cavity oil stirring flow characteristics of a servo motor pump is provided. The main working principle is that the simulation test device for the compact cavity oil stirring flow characteristics rotates under the drive motor to simulate the stirring of the oil in the compact cavity of the servo motor pump's integrated rotor. At the same time, a friction pair leakage flow adjustment device is designed to more realistically simulate the axial flow of the leaked oil on the basis of the rotor's circumferential oil stirring. Combined with speed torque sensors, high-speed cameras and other sensing equipment, the servo motor pump's oil stirring loss torque and pollutant deposition flow characteristics can be measured. The specific structure of the comprehensive test platform is as follows:

[0046] The oil supply pump motor 23 drives the oil supply pump 24 to rotate through the coupling, sucks oil from the oil tank 27-1 and outputs high-pressure oil to provide a power oil source for the comprehensive test platform. At the same time, a loading overflow valve 28 is provided in the bypass to load the system. The control system changes the system pressure by changing the solenoid valve signal.

[0047] The bypass is equipped with a contaminant tracer particle chamber 30 and is connected to the main oil inlet circuit via a butterfly valve 31. High-pressure oil passes through a one-way valve 25-1 and a gear flowmeter 26-2 before entering the simulated test device 33 through the oil-passing end cap 1. Any leaked oil inside the simulated test device is discharged through the leakage port 14, then passes through the one-way valve 25-2, the gear flowmeter 26-2, and the filter 29 before returning to the oil tank 27-2.

[0048] Check valves 25-1 and 25-2 on the high-pressure oil line and return oil line prevent hydraulic oil backflow, protecting the pump source and system components. Gear flowmeters 26-1 and 26-2 on the high-pressure oil line and return oil line measure flow rates in their respective lines. Filter 29 filters impurities from the hydraulic oil, ensuring system cleanliness and reliability. Pressure sensor 27 and temperature sensor 32 are installed in the high-pressure circuit to monitor system circuit pressure and temperature.

[0049] A high-speed drive motor 35 is connected to a speed and torque sensor 34 via a coupling. The other end of the speed and torque sensor 34 is connected to a simulated test device 33. The high-speed drive motor 35 rotates the simulated test device 33, stirring the oil inside the servo motor pump. The speed and torque sensor 34 measures the speed and torque of the simulated test device in real time.

[0050] A laser source 37 and two high-speed cameras 36 are located adjacent to the test platform, facing the simulated test apparatus 33. A data acquisition and control system 38 collects pressure, temperature, flow, speed, torque, and visual flow field imaging information from the test platform. It then controls the oil pump drive motor 23, high-speed drive motor 35, and loading relief valve 28 according to command requirements.

[0051] The measurement of the oil stirring loss torque is achieved in the following way. First, start the oil supply pump motor 23 to drive the oil supply pump 24 to supply oil, adjust the loading overflow valve 28 to the set pressure to load the system, and the pressurized oil enters the simulated test device through the oil end cover 1 on the simulated test device 33. Inside the simulated test device, by adjusting the gap δ1 between the end face of the plunger slipper assembly 6 and the end face of the threaded hole of the cylinder body 19, the gap δ2 between the plunger slipper assembly 6 and the slipper pair leakage adjustment baffle 7, and the gap δ3 between the cylinder body 19 and the distribution pair leakage adjustment baffle 4, the leakage oil of the three major friction pairs is truly simulated. Secondly, the speed of the drive motor 35 is adjusted to the set speed through the data acquisition and control system 38, and the speed torque sensor 34 records the driving torque T under the current working conditions. w Then, drain the oil in the simulated test device through the oil drain port, adjust the pressure and speed to the same working conditions, and record the torque value T under the no oil stirring condition again. d Finally, the difference between the two measured data is the oil stirring loss torque T of the servo motor pump in the compact cavity. c .

[0052] (5)

[0053] The contaminant deposition flow characteristics are achieved in the following manner. First, the oil supply pump motor 23, loading relief valve 28, and high-speed drive motor 35 are adjusted to the set pressure and speed. Second, a laser source emits a sheet laser beam, which penetrates the transparent acrylic material of the pump housing 4 and motor housing 16, illuminating a section of the flow field within the simulated test device 33. The butterfly valve 31 is then opened to release the tracer particles within the contaminant tracer particle chamber 30, simulating the wear debris contaminant particles within the motor pump. For measuring the oil agitation flow field, polystyrene, polyamide, or hollow glass microspheres with a diameter of 5-100 μm are typically used as tracer particles to ensure sufficient fluid tracking and high light scattering efficiency. The tracer particles enter the simulated test device 33 through the main circuit. The tracer particles within the agitated oil flow field act as a heat sink for the laser, allowing the laser to scatter to the sides of the flow field. A high-speed camera 36 is positioned perpendicular to the illuminated section and continuously captures the behavior of the illuminated flow field at set intervals, transmitting the data to the data acquisition and control system 38. The data acquisition and control system 38 processes the data to obtain the flow characteristics of the servo motor pump's oil stirring flow field and the pollutant deposition distribution information.

[0054] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A simulated test device for the flow characteristics of oil stirring in a compact cavity of a servo motor pump, characterized in that: The device includes an oil-through end cover, an oil-through shaft and a simulated pump body rotating assembly; The oil-passing end cover is connected to the oil-passing shaft, and the pressurized oil in the oil-passing end cover enters the interior of the simulated test device through the rotating oil-passing shaft; The oil-passing shaft is fixed to the cylinder body and rotates with the main shaft. The pressurized oil flows through the flow channel in the cylinder body and is divided into three parts: one part flows out from the plunger auxiliary nozzle flow channel and is ejected to the tapered end face of the plunger sliding shoe assembly to simulate the plunger auxiliary leakage; the other part flows out from the distribution auxiliary nozzle flow channel and is ejected to the distribution auxiliary leakage adjustment baffle to simulate the distribution auxiliary leakage; A part of it flows out from the nozzle channel of the sliding shoe pair and shoots toward the sliding shoe pair leakage adjustment baffle to simulate the leakage of the sliding shoe pair; The simulated pump body rotating assembly includes a cylinder body, a plunger shoe and a swash plate. The cylinder body is rigidly fastened to the main shaft and a gap is left between the cylinder body and the end face of the pump housing. The plunger and shoe are designed as an integrated structure.

2. The device for testing the flow characteristics of oil stirring in a compact cavity of a servo motor pump according to claim 1 is characterized in that: The leakage regulating baffle of the distribution pair is connected to the cylinder body, the leakage regulating baffle of the slipper pair is connected to the slipper of the plunger slipper assembly, and the plunger of the plunger slipper assembly is connected to the corresponding cylinder hole through fine thread.

3. The device for testing the flow characteristics of oil stirring in a compact cavity of a servo motor pump according to claim 1 is characterized in that: The method for adjusting the leakage flow of the plunger pair, the flow distribution pair and the slipper pair is as follows: the flow distribution pair leakage adjustment baffle is connected to the cylinder body by a fine-pitch thread, the fine-pitch thread has self-locking properties, and the distance between the end face of the flow distribution pair leakage adjustment baffle and the end face of the cylinder body is accurately adjusted by changing the number of turns of the flow distribution pair leakage adjustment baffle; the plunger of each plunger slipper assembly is connected to the corresponding cylinder hole by a fine-pitch thread, and the distance between the end face of the plunger slipper assembly and the end face of the cylinder hole is accurately adjusted by changing the number of turns of the plunger slipper assembly; the slipper pair leakage adjustment baffle is connected to the slipper of the plunger slipper assembly by a fine-pitch thread, and the distance between the end face of the slipper pair leakage adjustment baffle and the end face of the slipper is accurately adjusted by changing the number of turns of the slipper pair leakage adjustment baffle, thereby adjusting the leakage flow of the plunger pair, the flow distribution pair and the slipper pair.

4. The device for simulating the flow characteristics of oil stirring in a compact cavity of a servo motor pump according to claim 1 is characterized in that: The motor pump main shaft is rigidly connected to the cylinder body and the motor rotor, and the plunger shoe assemblies are fastened in the corresponding cylinder holes respectively. The overhanging length of each plunger shoe assembly is kept consistent and a certain gap is retained with the swash plate fixed on the connecting flange.

5. A comprehensive testing platform based on the simulated testing device for the oil stirring flow characteristics of the servo motor pump in a compact cavity according to any one of claims 1 to 4, characterized in that: The platform includes: a simulated test device, a fuel supply pump, a fuel tank, a contaminant tracer particle chamber, a high-speed camera, and a data acquisition and control system; The oil supply pump is connected to the drive motor, and the pressure is regulated by the loading relief valve, and the oil is supplied to the simulated test device through the gear flowmeter and the one-way valve. The pollutant tracer particle chamber is connected to the main oil circuit through the butterfly valve, and the tracer particles enter the simulated test device along with the pressurized oil through the rotating oil shaft. The leaked oil of the simulated test device is discharged from the leakage oil port, and then returns to the oil tank after passing through a one-way valve, a gear flow meter, and a filter; the simulated test device is connected to a high-speed drive motor through a speed and torque sensor; The high-speed camera is facing the simulated test device; The data acquisition and control system is used to collect pressure signals, temperature signals, flow signals, speed signals, torque signals and visual flow field imaging information of the comprehensive test platform, and to regulate the drive motor, high-speed drive motor and loading overflow valve of the oil supply pump.

6. The comprehensive test platform according to claim 5, characterized in that: The loading relief valve is adjusted to the set pressure, the drive motor speed is adjusted to the set speed, and the drive torque under the current working conditions is measured using the speed-torque sensor. The oil in the simulated test device is then drained through the oil drain port. The pressure and speed are adjusted to the same working conditions, and the torque value under the no-oil-stirring condition is recorded again. Finally, the difference between the two measured data is taken to obtain the oil-stirring loss torque of the servo motor pump in the compact cavity.

7. The comprehensive test platform according to claim 5, characterized in that: Adjust the oil supply pump motor, loading relief valve, and high-speed drive motor to the set working conditions; open the butterfly valve to release the tracer particles in the pollutant tracer particle chamber to simulate the wear debris contamination particles in the servo motor pump.

8. The comprehensive test platform according to claim 7, characterized in that: A high-speed camera, positioned perpendicular to the illuminated section, continuously captures the behavior of the illuminated flow field at set time intervals and transmits the data to a data acquisition and control system. Finally, the system processes the data to obtain the flow characteristics of the servo motor pump's oil-stirring flow field and information on pollutant deposition distribution.

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