System and method for testing dynamic performance of crankshaft oil seal of high-power diesel engine

Abstract

The invention provides a high-power diesel engine crankshaft oil seal dynamic performance test system and method, and relates to the technical field of internal combustion engine part testing, and the system comprises a rotary loading module, a suspension and support module, a vibration load simulation module, a measurement and control and data analysis module, and a test sealing cavity assembly. The rotary loading module specifically comprises an alternating current servo motor, a coupler, a main shaft, a rolling bearing and a dynamic torque sensor; the hanging and supporting module specifically comprises a four-column support, a flexible guide mechanism, an anti-rotation connecting rod, a height fine adjustment device and a dynamometer. The vibration load simulation module specifically comprises a linear motor, a controller and a grating encoder; a controller of the measurement and control and data analysis module is used for sending a rotating speed instruction to the rotary loading module and sending a vibration instruction to the vibration load simulation module; and the rotary loading module and the vibration load simulation module are used for sending a feedback signal to the measurement and control and data analysis module to form a control closed loop.

Description

Dynamic Performance Testing System and Method for Crankshaft Oil Seals of High-Power Diesel Engines Technical Field

[0001] This invention relates to the field of internal combustion engine component testing technology, and in particular to a dynamic performance testing system and method for crankshaft oil seals of high-power diesel engines. Background Technology

[0002] Crankshaft oil seals are critical components in diesel engines, isolating lubricating oil from the external environment. Their reliability directly impacts engine emissions, fuel consumption, and service life. As diesel engines evolve towards higher power density and higher burst pressure, crankshaft oil seals face harsh operating environments characterized by high speeds, high oil temperatures, high loads, and multi-dimensional vibration coupling. In actual operation, the radial runout and axial movement accompanying high-speed crankshaft rotation disrupt the stability of the oil film on the seal lip and alter the contact pressure distribution, becoming the core cause of seal failure. Therefore, accurately simulating these dynamic operating conditions and testing oil seal performance has become a core requirement for seal structure design and selection.

[0003] Current domestic and international oil seal bench testing technologies mainly employ mechanical eccentric structures to simulate radial runout and pneumatic pushers or mechanical lead screws to push the spindle to simulate axial movement. Performance evaluation focuses on macroscopic results such as leakage and frictional torque as core indicators, with some studies supplementing this with infrared thermal imagers to measure lip temperature and static pressure-sensitive paper to measure contact width. Benches are often designed for specific oil seal specifications, achieving corresponding testing functions through spindle boxes and drive systems.

[0004] However, existing solutions have core flaws: vibration loading is rigidly coupled, and the radial runout frequency is locked to the spindle speed, making it unable to simulate the rich asynchronous high-frequency or transient impact conditions of real machines, resulting in insufficient condition coverage. Simultaneously, the axial movement simulation response is slow, making it difficult to achieve high-frequency micro-load, and it easily induces overheating vibration in the equipment, interfering with test results. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a dynamic performance testing method for crankshaft oil seals of high-power diesel engines. This method can solve the problems of rigid coupling of vibration loading, locking of radial runout frequency with spindle speed, inability to simulate the rich asynchronous high-frequency or transient impact conditions of actual machines, and insufficient coverage of operating conditions. Furthermore, the axial runout simulation response is slow, making it difficult to achieve high-frequency micro-load, and easily causing overheating vibration of the equipment, interfering with the test results.

[0006] In a first aspect of the present invention, a dynamic performance testing system for crankshaft oil seal of a high-power diesel engine is proposed, comprising: a rotation loading module 1, a suspension and support module 2, a vibration load simulation module 3, a measurement and control and data analysis module, and a test sealing cavity assembly 4.

[0007] The rotary loading module 1 specifically includes: an AC servo motor, a coupling, a spindle, rolling bearings, and a dynamic torque sensor.

[0008] The suspension and support module 2 specifically includes: a four-post bracket, a flexible guide mechanism, an anti-rotation linkage, a height fine-tuning device, and a force gauge.

[0009] The vibration load simulation module 3 specifically includes: a linear motor, a controller, and a grating encoder.

[0010] The measurement, control and data analysis module specifically includes: a dynamic contact pressure monitoring device, a real-time leakage monitoring device, a temperature field monitoring device, and a vibration displacement monitoring device.

[0011] The test sealing cavity assembly 4 specifically includes: a sealing cavity, a multi-functional interface, and a media environment simulation device.

[0012] The rotary loading module 1 is connected to the test sealing cavity assembly 4.

[0013] The spindle and the oil seal lip of the sealing cavity form a dynamic sealing fit.

[0014] The suspension and support module 2 is connected to the test sealing cavity assembly.

[0015] The vibration load simulation module 3 drives the test sealed cavity assembly 4 to vibrate via a connecting rod.

[0016] The sensors of the measurement, control and data analysis module are installed on the test sealed cavity assembly 4.

[0017] The controller of the measurement, control and data analysis module is used to send speed commands to the rotation loading module 1 and vibration commands to the vibration load simulation module 3.

[0018] The rotary loading module 1 and the vibration load simulation module 3 are used to send feedback signals to the measurement and control and data analysis module to form a control closed loop.

[0019] A second aspect of the present invention provides a method for testing the dynamic performance of crankshaft oil seals in a high-power diesel engine, comprising: S1: calibrating the dynamic performance testing system according to the engine model under test.

[0020] S2: Static characteristic tests are performed on the tested model using a calibrated dynamic performance testing system.

[0021] S3: Construct the operating conditions of the tested model using the calibrated dynamic performance testing system.

[0022] S4: Based on the constructed operating conditions, acquire the test data of the tested model through the data acquisition system.

[0023] S5: Based on the test data, perform a performance evaluation on the tested model.

[0024] A third aspect of the present invention provides a readable storage medium on which a program or instructions are stored, and when the program or instructions are executed by a processor, the steps of the dynamic performance test method for high-power diesel engine crankshaft oil seals as described in the second aspect are implemented.

[0025] The beneficial effects of the technical solution provided by the embodiments of the present invention include at least the following: In the embodiments of the present invention, through a dual-module independent control architecture with complete decoupling of the rotary loading module and the vibration load simulation module, asynchronous working conditions and transient impact loads can be flexibly simulated, significantly improving the working condition coverage and accurately replicating the complex vibration characteristics of the actual crankshaft. Furthermore, through the design of the linear motor driving the housing and the relative motion, a horizontal linear motor with fast response speed is selected as the axial vibration actuator, meeting the dynamic and accuracy requirements of the actual working conditions. Simultaneously, by driving the housing to make the oil seal reciprocate axially relative to the stable rotating spindle, rather than directly pushing the high-speed rotating spindle, the overheating and vibration problems caused by axial force on the spindle bearing system are fundamentally avoided, eliminating the influence of equipment interference on the test results. Attached Figure Description

[0026] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0027] Figure 1 is a schematic diagram of the structure of a dynamic performance testing system for crankshaft oil seal of a high-power diesel engine provided in an embodiment of the present invention.

[0028] Figure 2 is a flowchart illustrating a dynamic performance test method for crankshaft oil seal of a high-power diesel engine provided in an embodiment of the present invention.

[0029] Explanation of reference numerals in the attached drawings: 1-Rotation loading module; 2-Suspension and support module; 3-Vibration load simulation module; 4-Test sealing cavity assembly. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0031] The following description, in conjunction with the accompanying drawings, details the method for testing the dynamic performance of crankshaft oil seals in high-power diesel engines, provided by the present invention, through specific embodiments and application scenarios.

[0032] Referring to Figure 1 in the specification, a structural schematic diagram of a dynamic performance testing system for crankshaft oil seals of a high-power diesel engine provided in an embodiment of the present invention is shown.

[0033] This invention provides a dynamic performance testing system for crankshaft oil seals of high-power diesel engines, comprising: a rotation loading module 1, a suspension and support module 2, a vibration load simulation module 3, a measurement and control and data analysis module, and a test sealing cavity assembly 4.

[0034] The rotary loading module 1 specifically includes: an AC servo motor, a coupling, a spindle, rolling bearings, and a dynamic torque sensor.

[0035] The suspension and support module 2 specifically includes: a four-post bracket, a flexible guide mechanism, an anti-rotation linkage, a height fine-tuning device, and a force gauge.

[0036] The vibration load simulation module 3 specifically includes: a linear motor, a controller, and a grating encoder.

[0037] The measurement, control and data analysis module specifically includes: a dynamic contact pressure monitoring device, a real-time leakage monitoring device, a temperature field monitoring device, and a vibration displacement monitoring device.

[0038] The test sealing cavity assembly 4 specifically includes: a sealing cavity, a multi-functional interface, and a media environment simulation device.

[0039] The rotary loading module 1 is connected to the test sealing cavity assembly 4.

[0040] The spindle and the oil seal lip of the sealing cavity form a dynamic sealing fit.

[0041] The suspension and support module 2 is connected to the test sealing cavity assembly.

[0042] The vibration load simulation module 3 drives the test sealed cavity assembly 4 to vibrate via a connecting rod.

[0043] The sensors of the measurement, control and data analysis module are installed on the test sealed cavity assembly 4.

[0044] The controller of the measurement, control and data analysis module is used to send speed commands to the rotation loading module 1 and vibration commands to the vibration load simulation module 3.

[0045] The rotary loading module 1 and the vibration load simulation module 3 are used to send feedback signals to the measurement and control and data analysis module to form a control closed loop.

[0046] In this embodiment of the invention, a dual-module independent control architecture, completely decoupled from the rotary loading module and the vibration load simulation module, flexibly simulates asynchronous working conditions and transient impact loads, significantly improving the working condition coverage and accurately replicating the complex vibration characteristics of a real machine crankshaft. Furthermore, through the design of the linear motor driving the housing and the relative motion, a fast-response horizontal linear motor is selected as the axial vibration actuator to meet the dynamic and accuracy requirements of real machine working conditions. Simultaneously, by driving the housing to make the oil seal reciprocate axially relative to the stable rotating spindle, rather than directly pushing the high-speed rotating spindle, the overheating and vibration problems caused by axial forces on the spindle bearing system are fundamentally avoided, eliminating the influence of equipment interference on the test results.

[0047] In one possible implementation, the AC servo motor is rigidly connected to one end of the dynamic torque sensor, and the other end of the dynamic torque sensor is coaxially connected to the spindle.

[0048] Couplings and dynamic torque sensors are used to transmit the power output from the AC servo motor to the spindle.

[0049] The spindle passes through the oil chamber housing of the test sealing chamber assembly 4 and forms a contact fit with the oil seal to be tested inside the housing.

[0050] The rolling bearing adopts a double bearing support structure.

[0051] Rolling bearings are coaxially fitted at both ends of the main shaft.

[0052] Specifically, the drive motor is a high-power AC servo motor with a rated power of 150kW, featuring a wide speed range (0-5000rpm) and high torque output capability, with a speed control accuracy better than 0.5%. The transmission chain connects the motor to the spindle via a high-rigidity, low-inertia coupling. The coupling must have certain axial and angular compensation capabilities to isolate the motor's own minute vibrations. The spindle adopts a modular design, covering a test range of Φ80mm~Φ150mm by changing different diameter bushings or shaft ends, specifically including Φ95mm (110 series free end), Φ96mm (150 series free end), Φ130mm (110 series output end), and Φ140mm (150 series output end). The spindle support uses high-precision rolling bearings, with the bearing housing fixed on a T-slot worktable, ensuring the spindle's rotational accuracy at high speeds (radial runout <5μm), providing a pure "zero" reference for vibration simulation. Torque monitoring specifically involves connecting a high-frequency dynamic torque sensor in series between the coupling and the spindle to monitor the oil seal friction torque and the power loss of the spindle system in real time, with a sampling rate >1kHz, in order to capture transient friction fluctuations.

[0053] In this embodiment of the invention, a dual-bearing support structure is coaxially fitted at both ends of the spindle, which ensures the coaxiality and stability of the spindle during high-speed rotation and reduces the interference of radial runout on oil seal testing. An AC servo motor is rigidly connected to the spindle coaxially via a coupling and a dynamic torque sensor. This not only compensates for coaxiality errors between components and buffers transmission vibrations to protect the motor and sensor, but also allows for real-time and accurate monitoring of frictional torque during spindle rotation, providing reliable data support for dynamic performance evaluation of the oil seal. Simultaneously, it enables stepless and precise adjustment of the spindle speed to adapt to the operating conditions of different tested machine models.

[0054] In one possible implementation, a four-post support straddles the main shaft.

[0055] The flexible guide mechanism is used to suspend the test sealed cavity assembly within the four-column support.

[0056] The four-post support integrates a height fine-tuning device and an anti-rotation linkage.

[0057] The four-column support, force gauge, flexible guide mechanism, and sealed cavity shell are connected in series.

[0058] Specifically, the four-pillar support is a highly rigid gantry frame spanning above the spindle. A flexible guiding mechanism allows the housing to move freely in the excitation direction (e.g., vertical or axial), but imposes strict constraints on other degrees of freedom (especially rotation about the spindle). A specialized anti-rotation linkage or flexible leaf spring mechanism is designed; the anti-rotation linkage mechanism provides high torsional stiffness while ensuring low damping of radial / axial vibrations, resisting the housing's tendency to overturn due to oil seal friction torque. A height fine-tuning device is integrated into the suspension system to precisely adjust the initial alignment (coaxiality) of the housing center with the spindle center during the test preparation phase, eliminating static eccentricity caused by gravity. A dynamometer is connected in series in the suspension link to monitor the excitation force and the reaction force on the housing, protecting the linear motor from overload.

[0059] In this embodiment of the invention, a four-column bracket spans the main shaft to form a stable support foundation. The integrated height fine-tuning device and anti-rotation linkage facilitate installation and debugging while limiting the rotational freedom of the sealing cavity assembly. The flexible guide mechanism suspending the sealing cavity assembly ensures vibration flexibility and constrains the direction of movement. The sequentially connected force transmission paths of each component allow the excitation reaction force to be accurately transmitted to the force gauge, enabling real-time monitoring of the reaction force to protect the linear motor. Simultaneously, it comprehensively ensures vibration loading accuracy, adapting to the testing requirements of dynamic coupling conditions.

[0060] In one possible implementation, the vibration load simulation module is used to generate controllable radial and axial vibrations. The excitation source abandons the mechanical eccentric mechanism and selects a high-thrust linear motor as the actuator. Linear motors have advantages such as fast response speed, no mechanical backlash, high control accuracy, and programmable stroke. The loading mechanism involves the linear motor's mover connected to the suspended oil chamber housing via a high-rigidity connecting rod. The system is configured with two independent linear motor units (or reconfigurable units), used to drive the housing to move in the vertical direction (simulating radial runout) and along the axial direction (simulating axial movement), respectively. The closed-loop control integrates a high-resolution grating encoder as a position feedback element to measure the actual displacement of the housing in real time, constructing a fully closed-loop position servo control system.

[0061] Furthermore, the specific performance indicators include: radial runout simulation, axial runout simulation, and waveform generation.

[0062] The radial runout simulation is as follows: displacement control range 0.07-0.14mm (typical operating conditions), with a maximum capacity of 1mm. Frequency response supports 65Hz (corresponding to an amplitude of 0.15mm).

[0063] The axial movement simulation is as follows: displacement control range is 0.18-0.349mm (typical operating conditions), with a maximum capacity of 1mm. Frequency response supports 50Hz (corresponding to an amplitude of 0.35mm).

[0064] The waveform generation specifically involves the controller generating sine waves, triangle waves, square waves, or importing measured road spectrum signals.

[0065] In this embodiment of the invention, a high-thrust linear motor is used to replace the mechanical eccentric mechanism. It has no backlash, fast response, and high control accuracy. The two independent units can respectively realize radial and axial vibration simulation. Combined with the full closed-loop control of the grating encoder, it can cover a wide range of displacements and frequencies and generate multiple types of waveforms to accurately reproduce real working conditions.

[0066] In one possible implementation, the dynamic contact pressure monitoring device specifically comprises: miniature high-frequency dynamic pressure sensors evenly embedded at the bushing position below the oil seal lip or inside the oil seal skeleton. The pressure fluctuation waveform of the lip contact area is acquired in real time, and the minimum value of the waveform is used to calculate the minimum contact pressure. ).

[0067] The real-time leakage monitoring device is specifically a leakage recovery unit, designed with an oil collection tank on the air side of the oil seal, which collects leaked oil by gravity or slight negative pressure. For minor leaks, a high-precision electronic balance weighing method (mass method) is used. For larger leaks, a Coriolis mass flow meter is used. Data is automatically recorded and a leakage rate curve is generated.

[0068] The temperature field monitoring device specifically includes: contact monitoring and non-contact monitoring. Contact monitoring involves drilling holes in the housing near the oil seal lip and embedding miniature K-type thermocouples to monitor the "lip temperature." Non-contact monitoring, when conditions permit, involves using an infrared thermal imager through a specially designed window to monitor the temperature distribution on the shaft surface and in the lip contact area.

[0069] The vibration displacement monitoring device specifically includes: directly reading data from the grating encoder and using a triaxial accelerometer mounted on the housing to verify the fidelity of the vibration waveform.

[0070] In this embodiment of the invention, pressure, leakage, temperature field, and vibration displacement monitoring modules are integrated in multiple dimensions. Each module adopts a precise and adapted monitoring method to comprehensively capture key parameters of the oil seal's dynamic operating conditions, providing real, complete, and reliable data support for subsequent performance evaluation.

[0071] In one possible implementation, the test sealing chamber assembly specifically comprises a front flange, a chamber body, and a rear cover plate. The front flange is equipped with a standard oil seal flange sleeve for mounting the oil seal to be tested. The chamber body has pre-drilled inlet, outlet, and vent ports, as well as multiple sensor mounting holes. A stabilizing bottle is connected to the oil inlet circuit to buffer minor changes in the chamber volume caused by housing vibration, maintaining stable oil pressure (rated 3 bar, maximum 10 bar). A heating system is used to circulate heating via an external oil station to simulate engine oil temperature (room temperature to 150°C).

[0072] In this embodiment of the invention, a split structure is adopted and equipped with a standard oil seal flange sleeve, which facilitates quick disassembly and replacement of the oil seal to be tested. Multiple types of interfaces are reserved to flexibly arrange various monitoring sensors. The pressure stabilizing bottle and heating system can accurately simulate the oil pressure and temperature conditions of the actual machine, ensuring that the test environment is highly consistent with the actual machine condition.

[0073] Referring to Figure 2 in the specification, a flowchart illustrating a method for testing the dynamic performance of crankshaft oil seals in a high-power diesel engine, as provided in an embodiment of the present invention, is shown.

[0074] S1: Calibrate the dynamic performance testing system according to the model being tested.

[0075] For example, select a simulated spindle and oil seal flange sleeve with the corresponding diameter (e.g., Φ96mm) according to the model being tested, and install them in place. Press the oil seal to be tested into the flange sleeve, and attach a miniature pressure sensor to a key position on the oil seal (e.g., the back of the spring groove), or install a wireless pressure telemetry node at the corresponding position on the spindle. Using the height fine-tuning device of the suspension system, in conjunction with a laser alignment instrument, adjust the position of the oil chamber housing so that the oil seal lip coincides with the geometric center of the spindle, ensuring that the initial radial eccentricity is <0.01mm. Start the lubricating oil circulation system, heat it to the target temperature (e.g., 110°C), and use a pressure stabilizing bottle to stabilize the oil pressure in the chamber at 3 bar.

[0076] In this embodiment of the invention, the system can be specifically calibrated according to the specific operating parameters (such as speed, vibration characteristics, etc.) of different tested models, eliminating the inherent errors of sensors and actuators, providing an accurate benchmark for subsequent static characteristic testing and dynamic coupling condition construction, ensuring that the test data truly reflects the performance of the tested oil seal, while improving the system's adaptability to different models, and ensuring the reliability and persuasiveness of subsequent performance evaluation results.

[0077] S2: Static characteristic tests are performed on the tested model using a calibrated dynamic performance testing system.

[0078] In one possible implementation, S2 specifically includes sub-steps S201 to S205: S201: The critical point of change in contact pressure between the oil seal lip to be tested and the spindle is obtained through the measurement and control and data analysis module.

[0079] It should be noted that the system can accurately capture the critical point of change in the contact pressure between the oil seal lip and the spindle, providing a key benchmark for subsequent control of the linear motor to drive the housing to generate radial displacement. This avoids damage to the oil seal lip caused by blind loading, while also ensuring the accuracy of subsequent static radial stiffness curve fitting and improving the scientific rigor and reliability of static characteristic testing.

[0080] S202: Based on the critical point of change, control the linear motor to push the shell of the sealed cavity at a preset speed to generate radial displacement.

[0081] It should be noted that those skilled in the art can set the preset speed according to actual needs, and this invention does not limit this.

[0082] It should be noted that by using the critical point of contact pressure change as the precise control benchmark, the linear motor pushes the housing to generate radial displacement at a preset speed. This avoids damage to the oil seal lip caused by blind loading and can stably control the output rhythm of the displacement. This provides controllable and reliable loading conditions for subsequent acquisition of real-time radial displacement and contact pressure data and fitting of static radial stiffness curves, ensuring the scientific nature and accuracy of static characteristic testing.

[0083] S203: The real-time radial displacement and real-time contact pressure of the tested machine are obtained through the data acquisition system.

[0084] It should be noted that by synchronously acquiring real-time radial displacement and contact pressure data through the data acquisition system, the dynamic correspondence between the two can be accurately captured, avoiding errors caused by data lag or asynchrony. This provides a real and complete data source for subsequent data averaging and static radial stiffness curve fitting, ensuring the accuracy and scientific validity of the static characteristic test results.

[0085] S204: Average the real-time radial displacement and real-time contact pressure.

[0086] It should be noted that averaging the real-time radial displacement and contact pressure data can effectively filter out random noise and instantaneous interference during the test, reduce the impact of sensor acquisition errors on the data, and make the processed data more stable and representative. This provides an accurate and reliable data foundation for subsequent fitting of the static radial stiffness curve using the least squares method, ensuring the scientific validity and accuracy of the static characteristic test results.

[0087] S205: By using the least squares method, a static radial stiffness curve is fitted based on the processed real-time radial displacement and processed real-time contact pressure to complete the static characteristic test.

[0088] Least squares is a mathematical optimization method used for data fitting and parameter estimation. Its core objective is to solve for the optimal model parameters by minimizing the sum of squares of the errors between the observed data and the model's predicted values, so that the fitted model can best fit the changing patterns of the actual observed data.

[0089] It should be noted that fitting the processed radial displacement and contact pressure data using the least squares method can effectively reduce random error interference, accurately generate static radial stiffness curves, and quantify the stiffness characteristics of the oil seal lip. This not only achieves the core objective of static characteristic testing but also provides a key benchmark for subsequent oil seal performance analysis under dynamic coupling conditions, ensuring the scientific nature and data comparability of the entire testing system.

[0090] In this embodiment of the invention, static characteristic tests are carried out based on the calibrated test system. By accurately capturing the pressure critical point, synchronously collecting and processing data, and fitting the stiffness curve using the least squares method, the static stiffness characteristics of the oil seal can be quantified, and a precise benchmark can be provided for subsequent dynamic coupling condition tests, ensuring the scientific nature and data reliability of the entire test process.

[0091] S3: Construct the operating conditions of the tested model using the calibrated dynamic performance testing system.

[0092] In one possible implementation, S3 specifically includes sub-steps S301 to S303: S301: Simulate the operating conditions of the machine under test by dynamic coupling loading.

[0093] In one possible implementation, S301 specifically includes sub-steps S3011 and S3012: S3011: When the dynamic coupling loading includes rotational parameters, the spindle is controlled to adjust to a preset speed through the rotational loading module.

[0094] It should be noted that those skilled in the art can set the preset rotation speed according to actual needs, and this invention does not limit this.

[0095] It should be noted that by independently controlling the spindle to adjust to the preset speed through the rotary loading module, the rigid coupling limitation between the traditional test bench speed and vibration frequency can be eliminated, accurately matching the actual rotational conditions of the machine under test, ensuring the stability of the high-speed spindle rotation, providing a reliable benchmark for the subsequent superposition of radial and axial vibration loads, and avoiding speed fluctuations from interfering with the accuracy of dynamic coupling tests.

[0096] S3012: When dynamic coupling loading includes vibration parameters, the vibration motion of the crankshaft of the tested model is simulated by multiple linear motors.

[0097] Specifically, the multiple linear motors include: vertical linear motors and horizontal linear motors.

[0098] When the dynamic coupling load is in the radial runout mode, the housing of the sealing cavity drives the oil seal to reciprocate relative to the rotating spindle through a vertical linear motor to simulate the radial runout of the crankshaft.

[0099] When the dynamic coupling load is in the axial movement mode, the axial movement of the crankshaft is simulated by a horizontal linear motor.

[0100] When the dynamic coupling loading is in composite mode, the phase difference between the vertical linear motor and the horizontal linear motor is set.

[0101] Based on the phase difference, the spatial trajectory motion of the crankshaft is simulated by vertical and horizontal linear motors.

[0102] It should be noted that by independently driving multiple linear motors to simulate crankshaft vibration, the rigid coupling limitation between traditional test bench speed and vibration frequency is broken. The frequency and amplitude of radial and axial vibration can be flexibly set, accurately replicating the complex multidimensional vibration conditions of the real machine. This provides real and controllable loading conditions for oil seal dynamic sealing performance testing, greatly improving the effectiveness and persuasiveness of the test data.

[0103] In this embodiment of the invention, the test machine's operating conditions are simulated by dynamic coupling loading, enabling independent control of rotational speed and multidimensional vibration. This breaks the limitations of traditional rigid coupling, accurately reproduces the actual motion state of the crankshaft, provides a real and reliable operating condition basis for the dynamic sealing performance test of oil seals, and ensures the validity and persuasiveness of the test results.

[0104] S302: The controller reads the feedback from the grating encoder in real time.

[0105] It should be noted that by reading the displacement feedback of the grating encoder in real time through the controller, the instantaneous position deviation of the oil chamber housing vibration can be accurately captured, providing real-time and reliable input data for subsequent PID algorithm error calculation and current correction, ensuring the accuracy and waveform fidelity of vibration load simulation, and making the simulated working conditions more consistent with the actual state of the tested model.

[0106] S303: Feedback results are used to correct the drive current of the linear motor through a PID algorithm, thus completing the working condition configuration.

[0107] PID algorithm is short for Proportional Integral Derivative control algorithm, which is a classic and widely used closed-loop control algorithm.

[0108] In one possible implementation, S303 specifically includes sub-steps S3031 to S3034: S3031: Calculate the position error of the linear motor using a PID algorithm.

[0109] Specifically, the formula for calculating the position error of a linear motor is as follows:

[0110] Where e(k) represents the position error at time k, r(k) represents the target displacement read by the controller, y(k) represents the actual displacement fed back by the grating encoder, and k represents the control cycle.

[0111] It should be noted that by using the PID algorithm to accurately quantify the deviation between the actual displacement and the target displacement of the linear motor drive housing, a reliable data basis is provided for subsequent controller output calculation and current correction. It can keenly capture the positional shift in micro-amplitude high-frequency vibration, ensuring the timely response of closed-loop control and making the simulated crankshaft vibration trajectory more closely match the actual machine conditions.

[0112] S3032: Based on the position error, the controller output is calculated using a PID algorithm.

[0113] Specifically, the formula for calculating the controller's output is:

[0114] Where u(k) represents the motor current command value at time k, i.e., the output of the controller at time k, and K p K represents the proportionality coefficient. i K represents the integral coefficient. d Represents the differential coefficient. Let e(k) represent the cumulative deviation from time 0 to time k, e(k) represent the deviation at time k, and e(k-1) represent the deviation at time k-1.

[0115] It should be noted that the controller output is calculated based on the position error using a PID algorithm. This integrates the advantages of proportional fast correction, integral elimination of steady-state deviation, and derivative trend prediction, providing a precise control basis for subsequent current command generation. This ensures the timeliness and accuracy of the linear motor drive response, allowing the vibration trajectory of the oil chamber housing to strictly conform to the target working condition, and improving the accuracy of dynamic coupling testing.

[0116] S3033: Based on the output, obtain the current command signal of the linear motor corresponding to the controller.

[0117] It should be noted that the control quantity output by the PID algorithm can be accurately converted into a current command signal that can be recognized by the linear motor, thus building a key bridge between the control algorithm and the execution component. This provides a direct basis for the accurate correction of the subsequent drive current, ensuring the continuity of the closed-loop control process and the accuracy of command execution, thereby improving the accuracy of vibration condition simulation.

[0118] S3034: Corrects the magnitude and direction of the drive current of the linear motor according to the current command signal.

[0119] Specifically, the driver adjusts the magnitude and direction of the current supplied to the linear motor according to the instruction u(k). The linear motor generates a corresponding electromagnetic thrust to overcome the off-center load caused by multi-axis coupling, the inertial force of the sealed cavity, the oil seal friction force, and the elastic damping force, forcing the housing position to correct towards the target position, thereby ensuring the high fidelity of the actual vibration waveform.

[0120] It should be noted that by accurately correcting the magnitude and direction of the linear motor drive current according to the current command signal, the strength and direction of the motor thrust can be flexibly adjusted, effectively offsetting interference factors such as oil pressure fluctuations and oil seal friction, forcing the actual vibration trajectory of the oil chamber shell to strictly conform to the preset target, ensuring high precision and high fidelity of dynamic coupling working condition simulation, and providing reliable load conditions for oil seal dynamic sealing performance testing.

[0121] In this embodiment of the invention, the linear motor drive current is corrected by relying on grating feedback combined with PID algorithm to form a complete closed-loop control, which effectively cancels out various interference factors in the test, ensures high precision and high fidelity of working condition simulation, and makes the constructed working condition strictly fit the actual machine state, greatly improving the reliability of oil seal dynamic performance test data.

[0122] S4: Based on the constructed operating conditions, acquire the test data of the tested model through the data acquisition system.

[0123] The data to be measured include: spindle speed, housing vibration displacement, contact pressure signal, friction torque, and leakage.

[0124] In this embodiment of the invention, the data to be tested is acquired through a data acquisition system composed of multi-dimensional monitoring devices, which has both authenticity and completeness, providing comprehensive and reliable quantitative support for subsequent performance evaluation and ensuring the scientific nature and accuracy of the evaluation results.

[0125] S5: Based on the test data, perform a performance evaluation on the tested model.

[0126] In one possible implementation, S5 specifically includes sub-steps S501 to S504: S501: Extract stable operating segment data from the data to be tested.

[0127] It should be noted that extracting data from the stable operating phase of the test data can effectively eliminate invalid interference data during unstable phases such as equipment startup and shutdown, ensuring the authenticity and representativeness of the data used in subsequent data analysis, and greatly improving the accuracy and scientific nature of the oil seal dynamic sealing performance evaluation results.

[0128] S502: Calculate the maximum and minimum contact pressures for multiple vibration cycles in the stable operation data.

[0129] It should be noted that calculating the maximum and minimum contact pressures over multiple vibration cycles based on stable operating data can effectively avoid the random errors of single-cycle data, accurately reflect the pressure fluctuation range of the oil seal under dynamic operating conditions, and provide key extreme parameters for subsequent evaluation of its sealing reliability and fatigue resistance.

[0130] S503: Calculate pressure uniformity based on the maximum and minimum contact pressures.

[0131] It should be noted that calculating pressure uniformity based on the maximum and minimum contact pressure can intuitively quantify the pressure distribution stability of the oil seal under dynamic working conditions, avoid the one-sidedness of a single extreme parameter, provide key quantitative indicators for evaluating the sealing reliability and wear resistance of the oil seal, and greatly improve the comprehensiveness and scientific nature of performance analysis.

[0132] S504: Determine whether the pressure uniformity is less than the preset value and whether the leakage of the tested model is lower than the preset leakage. If yes, the tested model is qualified. Otherwise, the tested model is unqualified.

[0133] It should be noted that those skilled in the art can set preset values ​​for judgment according to actual needs, and this invention does not limit such settings.

[0134] It should be noted that those skilled in the art can set the preset leakage amount according to actual needs, and this invention does not limit this.

[0135] It should be noted that by combining pressure uniformity and leakage as dual indicators to determine the performance of the tested model, the one-sidedness of evaluation by a single parameter is avoided. By establishing a unified and objective judgment standard based on preset thresholds, qualified products with reliable sealing and strong adaptability to operating conditions can be accurately screened, which greatly improves the authority and credibility of the performance judgment results.

[0136] In this embodiment of the invention, by extracting stable data, calculating pressure extreme values ​​and uniformity, and combining leakage amount as a dual indicator to evaluate performance, the interference of single parameters and random data is avoided, an objective and unified judgment standard is established, the sealing reliability of the model is accurately measured, and the comprehensiveness and authority of the performance evaluation are greatly improved.

[0137] This invention provides a readable storage medium comprising: storing a program or instructions on the readable storage medium, wherein when the program or instructions are executed by a processor, the program or instructions implement the steps of the above-described dynamic performance test method for crankshaft oil seal of a high-power diesel engine, and can achieve the same technical effect. To avoid repetition, this invention will not elaborate further.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A dynamic performance testing system for crankshaft oil seals of a high-power diesel engine, characterized in that, include: The test sealing cavity assembly comprises a rotary loading module (1), a suspension and support module (2), a vibration load simulation module (3), a measurement and control and data analysis module, and a test sealing cavity assembly (4). The rotary loading module (1) specifically includes an AC servo motor, a coupling, a spindle, rolling bearings, and a dynamic torque sensor. The suspension and support module (2) specifically includes a four-column bracket, a flexible guide mechanism, an anti-rotation linkage, a height fine-tuning device, and a force gauge. The vibration load simulation module (3) specifically includes a linear motor, a controller, and a grating encoder. The measurement and control and data analysis module specifically includes a dynamic contact pressure monitoring device, a real-time leakage monitoring device, a temperature field monitoring device, and a vibration displacement monitoring device. The test sealing cavity assembly (4) specifically includes a sealing cavity, a multi-functional interface, and a medium ring. The device includes a simulation device; the rotary loading module (1) is connected to the test sealing cavity assembly (4); the main shaft and the oil seal lip of the sealing cavity form a dynamic sealing fit; the suspension and support module (2) is connected to the test sealing cavity assembly; the vibration load simulation module (3) drives the test sealing cavity assembly (4) to vibrate through a connecting rod; the sensor of the measurement and control and data analysis module is installed on the test sealing cavity assembly (4); the controller of the measurement and control and data analysis module is used to send the rotation speed command to the rotary loading module (1) and the vibration command to the vibration load simulation module (3); the rotary loading module (1) and the vibration load simulation module (3) are used to send feedback signals to the measurement and control and data analysis module to form a control closed loop.

2. The dynamic performance testing system for high-power diesel engine crankshaft oil seals according to claim 1, characterized in that, The AC servo motor is rigidly connected to one end of the dynamic torque sensor, and the other end of the dynamic torque sensor is coaxially connected to the main shaft; the coupling and the dynamic torque sensor are used to transmit the power output by the AC servo motor to the main shaft; the main shaft passes through the oil chamber housing of the test sealing chamber assembly (4) and forms a contact fit with the oil seal to be tested inside the housing; the rolling bearing adopts a double bearing support structure; the rolling bearing is coaxially sleeved at both ends of the main shaft.

3. The dynamic performance testing system for high-power diesel engine crankshaft oil seals according to claim 1, characterized in that, The four-column support spans the main shaft; the flexible guide mechanism is used to suspend the test sealing cavity assembly inside the four-column support; the four-column support integrates the height fine-tuning device and the anti-rotation linkage; the four-column support, the force gauge, the flexible guide mechanism, and the housing of the sealing cavity are connected in series.

4. A method for testing the dynamic performance of crankshaft oil seals in a high-power diesel engine, characterized in that, The method is applied to the dynamic performance testing system according to any one of claims 1 to 3; the method includes: S1: calibrating the dynamic performance testing system according to the model under test; S2: performing static characteristic tests on the model under test using the calibrated dynamic performance testing system; S3: constructing the operating conditions of the model under test using the calibrated dynamic performance testing system; S4: acquiring test data of the model under test using a data acquisition system based on the constructed operating conditions; S5: performing performance evaluation on the model under test based on the test data.

5. The method for testing the dynamic performance of crankshaft oil seals in a high-power diesel engine according to claim 4, characterized in that, S2 specifically includes: S201: Obtaining the critical point of change in contact pressure between the oil seal lip under test and the spindle through the measurement and control and data analysis module; S202: Controlling the linear motor to push the housing of the sealing cavity at a preset speed according to the critical point of change, generating radial displacement; S203: Obtaining the real-time radial displacement and real-time contact pressure of the tested model through the data acquisition system; S204: Averaging the real-time radial displacement and the real-time contact pressure; S205: Fitting a static radial stiffness curve based on the processed real-time radial displacement and processed real-time contact pressure using the least squares method to complete the static characteristic test.

6. The method for testing the dynamic performance of crankshaft oil seals in a high-power diesel engine according to claim 4, characterized in that, S3 specifically includes: S301: Simulating the working conditions of the tested machine model through dynamic coupling loading; S302: Reading the feedback of the grating encoder in real time through the controller; S303: Correcting the drive current of the linear motor through the feedback result using a PID algorithm to complete the working condition construction.

7. The method for testing the dynamic performance of crankshaft oil seals in a high-power diesel engine according to claim 6, characterized in that, S301 specifically includes: S3011: When the dynamic coupling loading includes rotational parameters, the spindle is controlled to adjust to a preset speed through the rotational loading module; S3012: When the dynamic coupling loading includes vibration parameters, the crankshaft vibration of the tested model is simulated through multiple linear motors.

8. The method for testing the dynamic performance of crankshaft oil seals in a high-power diesel engine according to claim 7, characterized in that, The plurality of linear motors include a vertical linear motor and a horizontal linear motor. When the dynamic coupling load is in radial runout mode, the vertical linear motor causes the housing of the sealing cavity to reciprocate relative to the rotating main shaft, thereby simulating the radial runout of the crankshaft. When the dynamic coupling load is in axial runout mode, the horizontal linear motor simulates the axial runout of the crankshaft. When the dynamic coupling load is in a composite mode, a phase difference is set between the vertical linear motor and the horizontal linear motor. Based on the phase difference, the vertical linear motor and the horizontal linear motor simulate the spatial trajectory motion of the crankshaft.

9. The method for testing the dynamic performance of crankshaft oil seals in a high-power diesel engine according to claim 7, characterized in that, S303 specifically includes: S3031: Calculating the position error of the linear motor using a PID algorithm; S3032: Calculating the output of the controller using a PID algorithm based on the position error; S3033: Obtaining the current command signal of the linear motor corresponding to the controller based on the output; S3034: Correcting the magnitude and direction of the drive current of the linear motor based on the current command signal.

10. The method for testing the dynamic performance of crankshaft oil seals in a high-power diesel engine according to claim 4, characterized in that, S5 specifically includes: S501: extracting stable operating segment data from the data to be tested; S502: calculating the maximum and minimum contact pressures of multiple vibration cycles in the stable operating segment data; S503: calculating pressure uniformity based on the maximum and minimum contact pressures; S504: determining whether the pressure uniformity is less than a preset value and whether the leakage of the tested model is less than a preset leakage; if so, the performance of the tested model is qualified; otherwise, the performance of the tested model is unqualified.

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