Sliding bearing-rotor system stability test system and method under complex alternating load

Abstract

The invention discloses a sliding bearing-rotor system stability test system and method under a complex alternating load, and relates to the field of rotating machinery test in mechanical engineering. According to the technical key points, a multi-direction and multi-frequency dynamic load is applied through a six-degree-of-freedom platform, and a complex vibration and stress environment in an actual working condition is simulated. In the testing process, a high-precision sensor and a multi-channel acquisition board card are used for monitoring the vibration characteristic and the rotating speed of the system in real time, it is guaranteed that signals of different positions and types can be synchronously acquired, and comprehensive system state information is provided. Then, in combination with time domain and frequency domain analysis technologies, key features are extracted from mass data by applying an advanced Fourier transform algorithm, the resonant frequency, modal characteristics and potential fault modes of the system are identified, and accurate evaluation of the stability of the system is realized. Experimental results show that the real-time monitoring and analyzing method can effectively improve the stability testing precision of the sliding bearing-rotor system under the complex alternating load, and powerful technical support is provided for engineering application. The method is used for evaluating the stability of the sliding bearing-rotor system under the complex alternating load.

Description

Technical Field

[0001] The present invention relates to the field of rotating machinery testing in mechanical engineering, and particularly to a stability testing system and method for a sliding bearing-rotor system under complex alternating loads. Background Art

[0002] Sliding bearing-rotor systems are widely used in various industrial equipment, such as steam turbines, compressors, pumps, etc. Their operating stability directly affects the safety and reliability of the entire mechanical equipment. Traditional stability tests of sliding bearing-rotor systems are usually carried out under static or relatively simple dynamic conditions, that is, considering constant loads or small-amplitude alternating loads with periodic changes. However, with the progress of technology, the application scope of many rotating machinery is wider and the environment is more severe. Especially for ships working at sea, complex working conditions such as actual working, longitudinal inclination, transverse inclination, bow inclination, stern inclination, pitching, and rolling will cause low-frequency and large-displacement vibrations, resulting in large and irregular changes in the loads acting on the sliding bearings. The complex alternating loads generated are one of the important reasons for the instability of the ship's sliding bearing-rotor system and are very likely to cause major safety accidents.

[0003] Existing testing methods often cannot accurately simulate the complex alternating loads under actual working conditions, resulting in deviations between the test results and the actual situation, and it is difficult to comprehensively evaluate the dynamic response characteristics and stability of the sliding bearing-rotor system. In addition, traditional methods often lack accuracy, have limited application ranges, and are difficult to process data. In order to achieve a more realistic test environment, in some cases, it is necessary to build large test benches, which increases a large amount of manpower input and test time.

[0004] For example, the document number CN115791168A is an existing patent document, which discloses a simulation testing system and method for a sliding bearing, including an environment simulation device to provide a first simulated working environment and a second simulated working environment for the sliding bearing, collecting feedback signals of the sliding bearing in the first simulated working environment and the second simulated working environment through a signal acquisition device, controlling the first simulated working environment and the second simulated working environment according to the feedback signals, and analyzing the feedback signals to obtain the test results of the sliding bearing, realizing the process simulation and dynamic simulation of the actual working conditions, and improving the accuracy of the sliding bearing test. However, it only targets the sliding bearing and is not suitable for the testing of the sliding bearing-rotor system, and its simulated working environment is not the working condition under complex alternating loads. Summary of the Invention

[0005] The technical problem to be solved by the present invention is:

[0006] In the prior art, there is no proposal for the stability test of the bearing-rotor system under complex alternating load conditions, and it is impossible to comprehensively and accurately evaluate the bearing-rotor system under complex alternating load conditions. The problems such as low test accuracy, difficult data processing, complex test bench construction, and excessive resource investment of the sliding bearing-rotor system under complex alternating load conditions have always been unsolved. For this reason, the present invention provides a stability test system and method for a sliding bearing-rotor system under complex alternating load.

[0007] The technical solution adopted by the present invention to solve the above technical problems:

[0008] A stability test system for a sliding bearing-rotor system under complex alternating load, the stability test system is used to test the stability of the sliding bearing-rotor system under complex alternating load conditions; the stability test system includes a sliding bearing-rotor system test bench, a complex alternating load applying device, and a monitoring and measuring system;

[0009] The sliding bearing-rotor system test bench includes a driving motor (3), a coupling (4), a thrust bearing assembly (5), at least two radial bearing seat assemblies (6), eddy current displacement sensor brackets (7) with the same number as the radial bearing seat assemblies (6), a driving motor bracket (8), and a bottom plate (9); the thrust bearing assembly (5) includes two thrust bearings (5-1), a thrust disk (thrust plate) (5-2) located between the two thrust bearings (5-1), two thrust bearing end caps (5-3) installed outside the two thrust bearings (5-1), and a thrust bearing seat (5-4) installed on the bottom plate (9); each radial bearing seat assembly (6) includes a radial sliding bearing (6-1), radial sliding bearing end caps (6-2) installed on both sides of the radial sliding bearing (6-1), and a radial sliding bearing seat (6-3) installed on the bottom plate (9); each eddy current displacement sensor bracket (7) is installed on the bottom plate (9) and close to a corresponding radial bearing seat assembly (6); the thrust bearing assembly (5) is close to the coupling (4), the at least two radial bearing seat assemblies (6) are far from the coupling (4), the motor (3) is installed on the bottom plate (9) through the driving motor bracket (8), the output shaft of the motor (3) is connected to the rotating shaft (1) through the coupling (4), and the rotating shaft (1) is sequentially installed on the two thrust bearings (5-1) and each radial sliding bearing (6-1); the disk (2-1) is installed at a specific position on the rotating shaft (1) according to the design requirements;

[0010] The complex alternating load applying device is a six-degree-of-freedom platform for outputting a rocking load that changes periodically with time. The sliding bearing-rotor system test bench and the object to be measured thereon are installed on the workbench surface of the six-degree-of-freedom platform. By inputting the rocking angles (rotation angles) in three directions (X-axis, Y-axis, Z-axis), displacements in three directions (X-axis, Y-axis, Z-axis), and period parameters to the six-degree-of-freedom platform, the period parameters include the changes in rotational angular velocities in three directions and the changes in displacement velocities in three directions (X-axis, Y-axis, Z-axis); thereby, a complex alternating load is applied to the sliding bearing-rotor system test bench on which the object to be measured is installed.

[0011] The monitoring and measuring system includes eddy current displacement sensors (10) with a quantity twice that of the radial sliding shafts, optoelectronic speed sensors (11), acquisition boards (12), and a processor (13). Two eddy current displacement sensors in mutually perpendicular directions are installed on each eddy current displacement sensor bracket (7). The optoelectronic speed sensor is installed on the output shaft of the drive motor (3) to measure its rotational speed; the processor (13) is configured with a test program for the stability of the sliding bearing-rotor system under complex alternating loads. The eddy current displacement sensors (10) are used to measure the relative displacement between the rotating shaft (1) and the sensors and convert it into a voltage signal proportional to the displacement. After the voltage signal is subjected to signal conditioning and analog-to-digital conversion by the acquisition board (12), it is transmitted to the processor for real-time analysis and processing; meanwhile, the optoelectronic speed sensor (11) generates a pulse signal proportional to the rotational speed by detecting the rotation of the rotating shaft (1). After the pulse signal is subjected to signal conditioning and analog-to-digital conversion by the acquisition board (12), it is transmitted to the processor (13) for real-time analysis and processing; after the test program of the processor (13) analyzes and processes the acquired voltage signal and pulse signal simultaneously, an axis locus diagram of one rotation of the rotating shaft (1) and a vibration frequency spectrum diagram of the sliding bearing-rotor system that can be displayed through a display interface are obtained. According to the axis locus diagram and the vibration frequency spectrum diagram, it is judged whether the vibration amplitude of the rotating shaft exceeds the designed safety range, whether there are abnormal frequency components, and whether the axis locus diverges, and further, whether the stability of the sliding bearing-rotor system under complex alternating loads is good.

[0012] A method for testing the stability of a sliding bearing-rotor system under complex alternating loads. The stability test method is implemented based on a stability test system. The object to be measured of the stability measurement method is a sliding bearing-rotor system, and the working condition is under complex alternating loads; the sliding bearing-rotor system includes a rotating shaft (1) and multiple disk assemblies (2). Each disk assembly (2) includes a disk (2-1) and a shrink fit bushing (2-2). Each disk is installed on the rotating shaft (1) through the corresponding shrink fit bushing; the method includes the following steps:

[0013] S1. Installation and Configuration: Install the sliding bearing-rotor system under test on the sliding bearing-rotor system test bench, and then install the entire sliding bearing-rotor system test bench on the complex alternating load application device. The complex alternating load application device for simulating the swaying condition is connected to the ground.

[0014] S2. Set the Loading Program: Through the host computer of the complex alternating load application device, according to the actual working conditions or the preset load spectrum, use the interactive interface of the host computer to set the loading parameters of the complex alternating load application device (six-degree-of-freedom platform): swaying angle, moving displacement, and period.

[0015] S3. Start the Driving Motor; Start the driving motor (3) of the sliding bearing-rotor system test bench to make the rotating shaft reach the predetermined speed and maintain stable operation. Monitor the rotating speed and vibration amplitude of the rotating shaft through the test program in the monitoring and measurement system processor to ensure that the rotating speed fluctuates within the allowable range.

[0016] S4. Start the Complex Alternating Load Application Device (Six-Degree-of-Freedom Platform); Apply complex alternating loads to the sliding bearing-rotor system according to the preset loading program in step S2. The control system of the complex alternating load application device will adjust the output of each actuator in real time to ensure that the change of the load meets the set requirements.

[0017] S5. Data Acquisition: Conduct data acquisition through the processor of the monitoring and measurement system. During the entire test process, the eddy current displacement sensor (10) collects the displacement and vibration parameters of the rotating shaft (1) in real time; the optoelectronic speed sensor (11) collects the rotating speed of the rotating shaft (1) in real time. The eddy current displacement sensor (10) and the optoelectronic speed sensor (11) synchronously record the data of multiple channels at a high sampling rate through the acquisition board to ensure the integrity and accuracy of the data.

[0018] S6. Data Processing: Conduct data processing through the processor of the monitoring and measurement system. Use the test program to conduct preliminary processing on the collected data: filtering and calibration; use the test program to conduct in-depth analysis on the collected data to extract characteristic values: time-domain diagram, frequency spectrum diagram, rotating speed, and shaft center locus; use the MATLAB script file to process the data at each rotating speed and generate a report for intuitive and concise analysis of the stability of the sliding bearing-rotor system under complex alternating loads.

[0019] S7. Data Analysis: Conduct data analysis through the processor of the monitoring and measurement system. According to the extracted characteristic values, evaluate the stability of the sliding bearing-rotor system under complex alternating loads. The specific evaluation indicators are whether the vibration amplitude exceeds the safety range, whether there are abnormal frequency components, and whether the shaft center locus diverges.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] The present invention applies dynamic loads in multiple directions and frequencies through a six-degree-of-freedom platform to simulate the complex vibration and stress environment in actual working conditions. During the test, high-precision sensors (such as eddy current displacement sensors and optoelectronic speed sensors) and multi-channel acquisition boards are used to monitor the vibration characteristics and speed of the system in real time, ensuring that signals at different positions and types can be synchronously acquired, providing comprehensive system status information. Then, combining time-domain and frequency-domain analysis techniques and applying the fast Fourier transform (FFT) algorithm, key features are extracted from the massive data to identify the resonance frequency, modal characteristics, and potential failure modes of the system, realizing the accurate evaluation of the system stability. The experimental results show that the real-time monitoring and analysis method of the present invention can effectively improve the stability test accuracy of the sliding bearing-rotor system under complex alternating loads, providing strong technical support for engineering applications. The specific advantages are manifested in the following aspects:

[0022] 1) By applying complex alternating loads rotating around the coordinate axis directions through a six-degree-of-freedom platform, the dynamic response of the sliding bearing-rotor system in actual operation can be truly reproduced; compared with traditional methods, the present invention can more accurately simulate complex alternating loads, ensuring that the test conditions are highly consistent with the actual operating environment, and avoiding errors caused by simplified assumptions;

[0023] 2) High-speed and high-resolution data acquisition devices are adopted to synchronously record the output signals of multiple sensors, ensuring the integrity and accuracy of the data; traditional test methods often result in data loss or inaccuracy due to insufficient sampling rate or limited sensor accuracy, while the present invention effectively solves these problems through advanced data acquisition technology.

[0024] 3) The test data is processed and feature-extracted in real time using the written graphical programming language; through means such as frequency-domain analysis and time-frequency analysis, the data interpretation process is simplified, potential failure modes and abnormal conditions are identified, early warnings are given, and improvement suggestions are put forward.

[0025] 4) Key components such as sensors and data acquisition cards support the plug-and-play function, and users can quickly start the test without complex configuration. This feature makes the setup and operation of the test bench simpler, reducing the possibility of human errors.

[0026] The present invention is used to evaluate the stability of the sliding bearing-rotor system under complex alternating loads. Brief Description of the Drawings

[0027] The present invention can be better understood by referring to the description given below in conjunction with the accompanying drawings, which are included in and form a part of this specification together with the following detailed description, and are used to further illustrate the preferred embodiments of the present invention and explain the principles of the present invention.

[0028] Figure 1 Front view of a stability test system for a sliding bearing - rotor system under impact load according to the present invention ( Figure 1 below the bottom plate 9 is a complex alternating load applying device);

[0029] Figure 2 Stereogram of a stability test system for a sliding bearing - rotor system under impact load according to the present invention;

[0030] Figure 3 Exploded view of the disc assembly according to the present invention;

[0031] Figure 4 Exploded view of the radial bearing housing assembly according to the present invention;

[0032] Figure 5 Exploded view of the thrust bearing assembly according to the present invention;

[0033] Figure 6 Schematic diagram of the acquisition board card and the processor according to the present invention;

[0034] Figure 7 Schematic diagram of the process flow of a stability test system and method for a sliding bearing - rotor system under complex alternating load according to the present invention;

[0035] Figure 8 Verification diagram of the technical effects according to the present invention;

[0036] Figure 9 Comparison schematic diagram of the stability test results of a sliding bearing - rotor system under complex alternating load according to the present invention. Detailed implementation manners

[0037] In order to enable those skilled in the art to better understand the solution of the present invention, the exemplary embodiments or examples of the present invention will be described below in conjunction with the attached Figures 1-9 It is obvious that the described embodiments or examples are only a part of the embodiments or examples of the present invention, rather than all of them. All other embodiments or examples obtained by those of ordinary skill in the art based on the embodiments or examples in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] In conjunction with the attached Figures 1 to 9To illustrate the implementation of a stability test system and method for a sliding bearing-rotor system under complex alternating loads according to the present invention:

[0039] A stability measurement system for a sliding bearing-rotor system under complex alternating loads provided by the present invention includes a sliding bearing-rotor system test bench, a complex alternating load application device, and a monitoring and measurement system. The complex alternating load application device can be a six-degree-of-freedom platform produced by Nanjing All-Controlled Aviation Technology Co., Ltd., with the model QK2009.18-00-00, which can output a rocking load that changes periodically with time.

[0040] The stability test system for a sliding bearing-rotor system under complex alternating loads described in this embodiment is used to test the stability of the sliding bearing-rotor system under complex alternating load conditions. The stability test system includes a sliding bearing-rotor system test bench, a complex alternating load application device, and a monitoring and measurement system.

[0041] The sliding bearing-rotor system test bench includes a driving motor 3, a coupling 4, a thrust bearing assembly 5, at least two radial bearing seat assemblies 6, eddy current displacement sensor brackets 7 with the same quantity as the radial bearing seat assemblies 6, a driving motor bracket 8, and a base plate 9. The thrust bearing assembly 5 includes two thrust bearings 5-1, a thrust disk (thrust plate) 5-2 located between the two thrust bearings 5-1, two thrust bearing end covers 5-3 installed outside the two thrust bearings 5-1, and a thrust bearing seat 5-4 installed on the base plate 9. Each radial bearing seat assembly 6 includes a radial sliding bearing 6-1, radial sliding bearing end covers 6-2 installed on both sides of the radial sliding bearing 6-1, and a radial sliding bearing seat 6-3 installed on the base plate 9. Each eddy current displacement sensor bracket 7 is installed on the base plate 9 and close to a corresponding radial bearing seat assembly 6. The thrust bearing assembly 5 is close to the coupling 4, and the at least two radial bearing seat assemblies 6 are far from the coupling 4. The motor 3 is installed on the base plate 9 through the driving motor bracket 8. The output shaft of the motor 3 is connected to the rotating shaft 1 through the coupling 4. The rotating shaft 1 is sequentially installed on the two thrust bearings 5-1 and each radial sliding bearing 6-1. The disk 2-1 is installed at a specific position on the rotating shaft 1 according to the design requirements.

[0042] The complex alternating load application device is a six-degree-of-freedom platform for outputting a rocking load that changes periodically with time.

[0043] The sliding bearing-rotor system test bench and the object to be measured thereon are installed on the workbench surface of the six-degree-of-freedom platform. By inputting the swing angles (rotation angles) in three directions (X-axis, Y-axis, Z-axis), displacements in three directions (X-axis, Y-axis, Z-axis), and period parameters to the six-degree-of-freedom platform, the period parameters include the changes in rotational angular velocities in three directions and the changes in displacement velocities in three directions (X-axis, Y-axis, Z-axis); thus, a complex alternating load is applied to the sliding bearing-rotor system test bench on which the object to be measured is installed.

[0044] The monitoring and measuring system includes eddy current displacement sensors 10, optoelectronic speed sensors 11, acquisition boards 12, and processors 13, where the number of eddy current displacement sensors is twice that of the radial sliding shafts. Two eddy current displacement sensors perpendicular to each other at a 90-degree angle are installed on each eddy current displacement sensor bracket 7, and the optoelectronic speed sensor is installed on the output shaft of the drive motor 3 to measure its rotational speed; the processor 13 is configured with a test program for the stability of the sliding bearing-rotor system under complex alternating loads. The eddy current displacement sensor 10 is used to measure the relative displacement between the rotating shaft 1 and the sensor and convert it into a voltage signal proportional to the displacement. After the voltage signal is subjected to signal conditioning and analog-to-digital conversion by the acquisition board 12, it is transmitted to the processor for real-time analysis and processing; at the same time, the optoelectronic speed sensor 11 generates a pulse signal proportional to the rotational speed by detecting the rotation of the rotating shaft 1. After the pulse signal is subjected to signal conditioning and analog-to-digital conversion by the acquisition board 12, it is transmitted to the processor 13 for real-time analysis and processing; after the test program of the processor 13 analyzes and processes the acquired voltage signal and pulse signal simultaneously, an axis locus diagram of one rotation of the rotating shaft 1 and a vibration frequency spectrum diagram of the sliding bearing-rotor system that can be displayed through the display interface are obtained. According to the axis locus diagram and the vibration frequency spectrum diagram, it is judged whether the vibration amplitude of the rotating shaft exceeds the designed safety range, whether there are abnormal frequency components, and whether the axis locus diverges, and then whether the stability of the sliding bearing-rotor system under complex alternating loads is good.

[0045] The thrust bearing assembly further includes a sleeve 5-5 and a locking nut 5-6. Two thrust bearings 5-1 are installed on the thrust bearing seat 5-4, and the thrust disk 5-2 is installed on the inner side (i.e., between the two thrust bearings 5-1). The thrust disk 5-2 is sleeved on the rotating shaft 1. The sleeve 5-5 is installed between one thrust bearing 5-1 close to the coupling 4 and the rotating shaft 1, and the locking nut 5-6 is installed on the rotating shaft 1 close to the coupling 4. The locking nut 5-6 axially positions through the sleeve 5-5, (the locking nut 5-6 fixedly connects the sleeve 5-5 and the thrust disk 5-2), so that the thrust disk 5-2 rotates with the rotating shaft 1. The bearing end covers installed on both sides of the thrust bearing seat are used to prevent foreign objects from entering the bearing interior;

[0046] The radial bearing housing assembly includes a radial sliding bearing, a radial bearing housing, and bearing end covers. The radial sliding bearing is fixed to the radial bearing housing, and the bearing end covers are installed on both sides of the radial bearing housing to prevent foreign objects from entering the bearing interior. The radial bearing housing is fixed to the base plate, and the rotating shaft is installed inside the radial bearing to support rotation;

[0047] A coupling is installed at the output shaft (main shaft) position of the driving motor. The coupling is connected to the end of the rotating shaft. The disc assembly includes a disc and a shrink disc. The shrink disc is used to be placed inside the disc. The shrink disc and the disc (round disc) are installed on the rotating shaft by screws. The base plate 9 is rigidly fixed to the six-degree-of-freedom platform by bolts;

[0048] The complex alternating load applying device uses a six-degree-of-freedom platform produced by Nanjing All Control Aviation Technology Co., Ltd., model QK2009.18-00-00, which can simulate the swaying conditions of at least 5 levels of sea waves. Before measurement, it is connected to the ground by expansion bolts to maintain sufficient rigidity to avoid significant errors in test measurement; the operating parameters are pitching amplitude angle ±15°, period 4 - 10 s; rolling amplitude angle ±45°, period 3 - 14 s; the sliding bearing rotor system test bench (the sliding bearing-rotor system test bench with the object under test installed) completed by the above combination is fixed to the six-degree-of-freedom platform by bolts, and different swaying angle and period parameters are input through the six-degree-of-freedom platform control cabinet to apply complex alternating loads to the sliding bearing rotor system test bench;

[0049] The eddy current displacement sensors 10 are installed horizontally and vertically on the sensor bracket respectively. The sensor bracket is installed at the radial bearing support position. The optical encoder speed sensor is installed on the sensor bracket, and the sensor bracket is fixed to the support structure; the acquisition board card model is NI USB-4432, which can collect data on speed and vibration; the test program can collect, process, and display vibration and speed signals in real time.

[0050] A method for testing the stability of a sliding bearing-rotor system under complex alternating loads. The stability testing method is implemented based on a stability testing system for a sliding bearing-rotor system under complex alternating loads. The object under test of the stability measurement method is a sliding bearing-rotor system, and the working condition is under complex alternating loads; the sliding bearing-rotor system includes a rotating shaft 1 and multiple disc assemblies 2. Each disc assembly 2 includes a disc 2-1 and a shrink disc 2-2. Each disc is installed on the rotating shaft 1 through the corresponding shrink disc;

[0051] The stability testing method includes the following steps:

[0052] S1. Installation and Configuration: Install the sliding bearing-rotor system to be measured on the sliding bearing-rotor system test bench, and then install the entire sliding bearing-rotor system test bench on the complex alternating load applying device, which is connected to the ground for simulating the complex alternating load in the swaying condition; (where S1 also includes: Assemble all components onto the test bench according to the design requirements to ensure firm connections of all components and accurate positions of sensors; Check whether each actuator of the six-degree-of-freedom platform is working properly and conduct preloading tests to ensure the stability of the system;)

[0053] S2. Set the Loading Program: Through the host computer of the complex alternating load applying device, according to the actual working condition or the preset load spectrum, use the interactive interface of the host computer to set the loading parameters of the complex alternating load applying device (six-degree-of-freedom platform): swaying angle, moving displacement, period;

[0054] S3. Start the Driving Motor; Start the driving motor 3 of the sliding bearing-rotor system test bench to make the rotating shaft reach the predetermined speed and maintain stable operation. Monitor the rotating speed and vibration amplitude of the rotating shaft through the test program in the monitoring and measuring system processor to ensure that the rotating speed fluctuates within the allowable range;

[0055] S4. Start the Complex Alternating Load Applying Device (Six-Degree-of-Freedom Platform); Apply complex alternating load to the sliding bearing-rotor system according to the loading program preset in step S2. The control system of the complex alternating load applying device will adjust the output of each of its actuators in real time to ensure that the change of the load meets the set requirements;

[0056] S5. Data Acquisition: Conduct data acquisition through the processor of the monitoring and measuring system. During the entire test process, the eddy current displacement sensor 10 continuously acquires the displacement and vibration parameters of the rotating shaft 1; the optoelectronic speed sensor 11 continuously acquires the rotating speed of the rotating shaft 1. The eddy current displacement sensor 10 and the optoelectronic speed sensor 11 Acquisition board Synchronously record data of multiple channels at a high sampling rate to ensure the integrity and accuracy of the data;

[0057] S6. Data Processing: Conduct data processing through the processor of the monitoring and measuring system. Use the test program to conduct preliminary processing on the acquired data: filtering, calibration; Use the test program to conduct in-depth analysis on the acquired data to extract characteristic values: time-domain diagram, frequency spectrum diagram, rotating speed, shaft center locus; Use the MATLAB script file to process the data at each rotating speed and generate a report for intuitive and concise analysis of the stability of the sliding bearing-rotor system under complex alternating loads;

[0058] S7. Data analysis: Data analysis is carried out by the processor of the monitoring and measurement system. According to the extracted characteristic values, the stability of the sliding bearing-rotor system under complex alternating loads is evaluated. The specific evaluation indexes are whether the vibration amplitude exceeds the safe range, whether there are abnormal frequency components, and whether the shaft center trajectory diverges.

[0059] For the stability test system and method of a sliding bearing-rotor system under complex alternating loads according to the present invention, please refer to Figure 7 , and the process is as follows: Under complex alternating load conditions, the eddy current displacement sensor 10 and the optoelectronic speed sensor 11 are used to collect the stability data of the sliding bearing-rotor system; through the data acquisition board 12, the data collected by the above sensors are transmitted to the processor 13; calibration operations are performed on the used eddy current displacement sensor and optoelectronic speed sensor to ensure that the voltage signal and pulse signal can be accurately converted into the corresponding displacement and rotational speed, and necessary filtering processing is implemented during this process to eliminate noise interference; for the experimental data obtained after preliminary processing, the Hamming window function is used for weighting and then the fast Fourier transform (FFT) is performed to improve the frequency resolution and reduce the spectrum leakage phenomenon; the data that has completed the FFT conversion is deeply analyzed, characteristic values are extracted from it, and a time domain diagram, a frequency spectrum diagram, a shaft center trajectory, and a rotational speed are generated; through the MATLAB script program, a comprehensive report including the time domain diagram, the frequency domain diagram, the shaft center trajectory, and the rotational speed is automatically generated, so as to more conveniently evaluate the stability of the sliding bearing-rotor system under complex alternating loads.

[0060] For the verification of the technical effects of the present invention, please refer to Figure 8 , Figure 8 shows the test results of the sliding bearing-rotor system under complex alternating loads using the test system method of the present invention, including the time domain diagram, the frequency domain diagram, the shaft center trajectory, and the rotational speed. Analysis can be carried out according to the characteristic values extracted from the test program to check whether there are abnormal frequency components, whether the vibration amplitude exceeds the safe range, and whether the shaft center trajectory diverges, so as to evaluate whether the stability of the sliding bearing-rotor system under complex alternating loads is good. As Figure 8 shown, the test working condition is set as the roll amplitude angle of ±20° and the period of 3 s, and the six-degree-of-freedom platform is started. When the rotational speed of the rotating shaft is 5357 r / min, the following phenomena are observed: The signal in the time domain diagram shows an irregular sine waveform; the shaft center trajectory shows divergence and presents a petal shape; in the frequency domain diagram, in addition to the rotational frequency of the rotating shaft, abnormal low-frequency components also appear, and the vibration amplitude increases significantly. Based on the above characteristics, it can be judged that there is a stability problem with the sliding bearing-rotor system, and its operating state significantly deviates from the ideal stable condition, indicating potential safety hazards and performance degradation.

[0061] Schematic diagram for comparing the stability test results of a sliding bearing-rotor system under complex alternating loads. Please refer to Figure 9 . The comprehensive report automatically generated by the MATLAB script file includes information such as time-domain diagrams, frequency-domain diagrams, shaft center orbits, and rotational speeds. The test conditions are a roll amplitude of ±20° and a period of 3 s. When the rotational speed of the rotating shaft increases from 5300 to 5357 r / min, in the time-domain diagram, the originally stable sine waveform evolves into a non-sine wave; in the frequency-domain diagram, abnormal low frequencies and high vibration amplitudes appear; the shaft center orbit changes from a stable ellipse to a divergent petal shape. These changes make it more convenient and intuitive to evaluate the stability of the sliding bearing-rotor system under complex alternating loads.

[0062] Although the present invention has been described based on a limited number of embodiments, those skilled in the art in this technical field understand that other embodiments can be envisioned within the scope of the present invention thus described. For the scope of the present invention, the disclosure made of the present invention is illustrative rather than restrictive, and the scope of the present invention is defined by the appended claims.

Claims

1. A sliding bearing-rotor system stability test system under complex alternating loads, characterized in that: The stability test system is used to test the stability of the sliding bearing-rotor system under the working condition of complex alternating loads; the stability test system includes a sliding bearing-rotor system test bench, a complex alternating load application device, and a monitoring and measurement system; The sliding bearing-rotor system test bench comprises a drive motor (3), a coupling (4), a thrust bearing assembly (5), at least two radial bearing seat assemblies (6), eddy current displacement sensor brackets (7) having the same number as the radial bearing seat assemblies (6), a drive motor bracket (8) and a base plate (9); the thrust bearing assembly (5) comprises two thrust bearings (5-1), a thrust plate (thrust plate) (5-2) located between the two thrust bearings (5-1), two thrust bearing end covers (5-3) installed on the outside of the two thrust bearings (5-1), and a thrust bearing seat (5-4) installed on the base plate (9); each radial bearing seat assembly (6) comprises a radial sliding bearing (6-1), a thrust plate (5-2) installed on the radial sliding bearing (6-1), and a thrust bearing seat (5-4) installed on the base plate (9). ) on both sides of the radial sliding bearing end covers (6-2) and the radial sliding bearing seats (6-3) installed on the base plate (9); each eddy current displacement sensor bracket (7) is installed on the base plate (9) and close to a corresponding radial bearing seat assembly (6); the thrust bearing assembly (5) is close to the coupling (4), and the at least two radial bearing seat assemblies (6) are far away from the coupling (4); the motor (3) is installed on the base plate (9) through the driving motor bracket (8), the output shaft of the motor (3) is connected to the rotating shaft (1) through the coupling (4), and the rotating shaft (1) is installed on the two thrust bearings (5-1) and each radial sliding bearing (6-1) in sequence; the wheel disc (2-1) is installed at a specific position of the rotating shaft (1) according to design requirements; The complex alternating load applying device is a six-degree-of-freedom platform for outputting a swing load that changes periodically over time. The sliding bearing-rotor system test bench and the object to be tested thereon are installed on the working table of the six-degree-of-freedom platform. The six-degree-of-freedom platform is input with swing angles (rotation angles) in three directions (X-axis, Y-axis, and Z-axis), displacements in three directions (X-axis, Y-axis, and Z-axis), and periodic parameters, wherein the periodic parameters include changes in rotational angular velocities in three directions and changes in displacement velocities in three directions (X-axis, Y-axis, and Z-axis); thereby applying a complex alternating load to the sliding bearing-rotor system test bench on which the object to be tested is installed; The monitoring and measuring system comprises eddy current displacement sensors (10) whose number is twice that of radial sliding shafts, photoelectric speed sensors (11), acquisition boards (12), and processors (13). Each eddy current displacement sensor bracket (7) is equipped with two eddy current displacement sensors which are arranged in 90-degree directions to each other. The photoelectric speed sensor is installed on the output shaft of the driving motor (3) to measure its speed. The processor (13) is configured with a test program for the stability of the sliding bearing-rotor system under complex alternating loads. The eddy current displacement sensor (10) is used to measure the relative displacement between the rotating shaft (1) and the sensor, and convert it into a voltage signal proportional to the displacement. The voltage signal is subjected to signal conditioning and analog-to-digital conversion by the acquisition board (12), and then transmitted to the processor for real-time analysis. analysis and processing; at the same time, the photoelectric speed sensor (11) generates a pulse signal proportional to the speed by detecting the rotation of the rotating shaft (1), and the pulse signal is transmitted to the processor (13) for real-time analysis and processing after signal conditioning and analog-to-digital conversion by the acquisition board (12); the test program of the processor (13) simultaneously analyzes and processes the collected voltage signal and pulse signal, and obtains an axis trajectory diagram of the rotating shaft (1) rotating one circle and a vibration spectrum diagram of the sliding bearing-rotor system that can be displayed on the display interface, and judges whether the vibration amplitude of the rotating shaft exceeds the design safety range, whether there are abnormal frequency components, and whether the axis trajectory diverges according to the axis trajectory diagram and the vibration spectrum diagram, thereby obtaining whether the stability of the sliding bearing-rotor system under complex alternating loads is good.

2. A sliding bearing-rotor system stability test system under complex alternating loads according to claim 1, characterized in that: The thrust bearing assembly also includes a sleeve (5-5) and a locking nut (5-6). Two thrust bearings (5-1) are mounted on the thrust bearing seat (5-4), and a thrust plate (5-2) is mounted on the inner side (i.e., mounted between the two thrust bearings 5-1). The thrust plate (5-2) is sleeved on the rotating shaft (1). The sleeve (5-5) is mounted between a thrust bearing (5-1) close to the coupling (4) and the rotating shaft (1). The locking nut (5-6) is mounted on the rotating shaft (1) close to the coupling (4). The locking nut (5-6) is axially limited by the sleeve (5-5) (the locking nut 5-6 fixes the sleeve 5-5 and the thrust plate 5-2), so that the thrust plate (5-2) rotates with the rotating shaft (1). The bearing end covers mounted on both sides of the thrust bearing seat are used to prevent foreign matter from entering the interior of the bearing.

3. A sliding bearing-rotor system stability test system under complex alternating loads according to claim 1 or 2, characterized in that: The radial bearing seat assembly includes a radial sliding bearing, a radial bearing seat, and a bearing end cover. The radial sliding bearing is fixed on the radial bearing seat. The bearing end covers are installed on both sides of the radial bearing seat to prevent foreign matter from entering the bearing. The radial bearing seat is fixed on the base plate, and the rotating shaft is installed inside the radial bearing to support its rotation.

4. A sliding bearing-rotor system stability test system under complex alternating loads according to claim 3, characterized in that: A coupling is installed at the output shaft (main shaft) of the driving motor, and the coupling is connected to the end of the rotating shaft. The wheel assembly comprises a wheel and a tension sleeve, and the tension sleeve is used to be placed inside the disc. The tension sleeve and the disc are installed on the rotating shaft by screws, and the base plate (9) is rigidly fixed on the six-degree-of-freedom platform by bolts.

5. The sliding bearing-rotor system stability test system under complex alternating loads according to claim 3, characterized in that: The complex alternating load applying device can be a six-degree-of-freedom platform produced by Nanjing Quankong Aviation Technology Co., Ltd., model QK2009.18-00-00, which is used to output the swing load that changes periodically with time loaded on the sliding bearing-rotor system test bench where the sliding bearing-rotor system is installed.

6. A method for testing the stability of a sliding bearing-rotor system under complex alternating loads, characterized in that: The object to be measured in the stability measurement method is a sliding bearing-rotor system, and the working condition is a complex alternating load; the sliding bearing-rotor system comprises a rotating shaft (1), a plurality of wheel disc assemblies (2), each wheel disc assembly (2) comprises a wheel disc (2-1) and a tension sleeve (2-2), and each wheel disc is mounted on the rotating shaft (1) via a corresponding tension sleeve; and the method comprises the following steps: S1. Installation and configuration: The tested sliding bearing-rotor system is installed on the sliding bearing-rotor system test bench, and then the whole sliding bearing-rotor system test bench is installed on the complex alternating load application device, and the complex alternating load application device for simulating the swinging working condition is connected to the ground; S2. Setting the loading program: through the host computer of the complex alternating load applying device, according to the actual working conditions or the preset load spectrum, use the interactive interface of the host computer to set the loading parameters of the complex alternating load applying device (six-degree-of-freedom platform): swing angle, moving displacement, and period; S3, start the drive motor; start the drive motor (3) of the sliding bearing-rotor system test bench, make the shaft reach a predetermined speed, and keep stable operation, monitor the shaft speed and vibration amplitude through the test program in the monitoring and measurement system processor, and ensure that the speed fluctuates within the allowable range; S4, start the complex alternating load application device (six-degree-of-freedom platform); Applying a complex alternating load to the sliding bearing-rotor system according to the preset loading program in step S2, the control system of the complex alternating load applying device will adjust the output of each actuator in real time to ensure that the load change meets the set requirements; S5, data acquisition: data acquisition is performed through the processor of the monitoring and measuring system. During the entire test process, the eddy current displacement sensor (10) acquires the displacement and vibration parameters of the rotating shaft (1) in real time; the photoelectric rotation speed sensor (11) acquires the rotation speed of the rotating shaft (1) in real time. The eddy current displacement sensor (10) and the photoelectric rotation speed sensor (11) synchronously record the data of multiple channels at a high sampling rate through an acquisition board to ensure the integrity and accuracy of the data; S6. Data processing: Data processing is performed through the processor of the monitoring and measurement system. The collected data is preliminarily processed using the test program: filtering and calibration; the collected data is deeply analyzed using the test program to extract characteristic values: time domain diagram, spectrum diagram, speed, axis trajectory; the data at various speeds is processed using the MATLAB script file and a report is generated to provide an intuitive and concise analysis of the stability of the sliding bearing-rotor system under complex alternating loads; S7. Data analysis: Data analysis is performed through the processor of the monitoring and measurement system. Based on the extracted characteristic values, the stability of the sliding bearing-rotor system under complex alternating loads is evaluated. The specific evaluation indicators are whether the vibration amplitude exceeds the safety range, whether there are abnormal frequency components, and whether the axis trajectory diverges.

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