Experimental device for aeroengine gear damage test

Abstract

The invention relates to an experimental device for an aero-engine gear damage test. Comprising a gearbox, a control cabinet, an upper computer, a power system, a loading system, a lubricating oil temperature control system and a detection system, the control cabinet is in signal connection with the upper computer, the power system, the loading system, the lubricating oil temperature control system and the detection system; the first tested gear is installed on a first gear shaft of the power system and located in the gear box, the second tested gear is installed on a second gear shaft of the loading system and located in the gear box, and the first tested gear is meshed with the second tested gear; a control instruction is sent to the control cabinet through the upper computer, so that the control cabinet controls the power system, the loading system and the lubricating oil temperature control system to operate and controls the detection system to collect detection signals. And the detection precision of the aero-engine gear damage test is improved.

Description

Technical Field

[0001] This application relates to the field of aero-engine gear testing technology, and in particular to an experimental apparatus for testing aero-engine gear damage. Background Technology

[0002] Aero-engine gears are primarily assembled inside the transmission casing, mainly serving to transmit torque in both forward and reverse directions. As a core component of the aero-engine power transmission system, gears are prone to failure modes such as abrasive wear and fatigue pitting during long-term operation under complex conditions such as high speed, heavy load, and variable lubrication, severely affecting the reliability and safety of the transmission system. Statistics show that tooth surface contact fatigue (micro-pitting / sparging) and wear failure account for over 78% of typical gear failure modes. Therefore, conducting experimental research on gear wear and pitting, and accurately understanding their failure mechanisms and evolution laws, is crucial for gear optimization design, life prediction, and fault diagnosis.

[0003] Current gear damage testing methods fail to reflect the actual operating conditions of gear transmission devices due to several shortcomings of existing gear testing equipment: First, their ability to simulate operating conditions is limited, making it difficult to reproduce complex actual operating conditions such as high speed, dynamic load, and variable lubrication conditions; second, their testing methods are not comprehensive enough, often only collecting single signals such as temperature or vibration, lacking comprehensive monitoring of wear mechanism identification, micromorphological evolution, and wear particle characteristics, making it difficult to comprehensively reflect the failure characteristics of gear wear and pitting, and lacking real-time monitoring capabilities for tooth surface micromorphology; third, data processing mostly remains at the level of raw data acquisition, lacking the ability to deeply extract and intelligently identify fault characteristics.

[0004] Therefore, the detection accuracy of current aircraft engine gear damage tests is low. Summary of the Invention

[0005] Therefore, it is necessary to provide an experimental device for testing aero-engine gear damage that can improve the detection accuracy of aero-engine gear damage testing, addressing the aforementioned technical problems.

[0006] An experimental apparatus for testing gear damage in aero-engines, the apparatus comprising: a gearbox, a control cabinet, a host computer, a power system, a loading system, a lubricating oil temperature control system, and a detection system; The control cabinet is connected to the host computer, power system, loading system, lubricating oil temperature control system, and detection system for signal transmission. The first test gear is mounted on the first gear shaft of the power system and located inside the gearbox; the second test gear is mounted on the second gear shaft of the loading system and located inside the gearbox; the first test gear meshes with the second test gear. The host computer sends control commands to the control cabinet, which then controls the operation of the power system, the loading system, and the lubricating oil temperature control system, and controls the detection system to collect detection signals.

[0007] In one embodiment, the power system includes: a motor, a first coupling, a second coupling, a third coupling, a first gear shaft, a torque meter, and a first encoder; The motor is located on the right side of the first coupling, and the motor is connected to one end of the first gear shaft through the first coupling. The torque meter is located on the left side of the first coupling and connected to the first gear shaft. The second coupling rigidly connects the first test gear output from the gearbox to the torque meter; The first encoder is connected to the other end of the first gear shaft via the third coupling.

[0008] In one embodiment, the loading system includes: a magnetic powder brake, a second gear shaft, a cooling pump, a fourth coupling, a fifth coupling, and a second encoder; The cooling pump is connected to the magnetic powder brake, which is connected to one end of the second gear shaft via a fourth coupling. The second encoder is connected to the other end of the second gear shaft via a fifth coupling.

[0009] In one embodiment, the lubricating oil temperature control system includes: a heating and cooling device, a temperature sensor, a lubricating oil tank, a lubricating oil pipe, a lubricating oil pump, and an electromagnetic flow control valve; The bottom of the lubricating oil tank is provided with an oil sample collection interface. The heating and cooling device is integrated into the lubricating oil tank. The oil inlet of the lubricating oil pump is connected to the outlet of the lubricating oil tank through the lubricating oil pipe. The oil outlet of the lubricating oil pump delivers lubricating oil to the lubrication inlet in the gearbox through the lubricating oil pipe. The electromagnetic flow control valve is installed between the oil outlet of the lubricating oil pump and the gearbox. By connecting an oil pipe between the lubricating oil outlet of the gearbox and the lubricating oil tank, the lubricating oil in the gearbox is transported back to the lubricating oil tank; The temperature sensor is installed in the lubricating oil tank of the lubricating oil temperature control system, and the temperature sensor is connected to the heating and cooling device via a signal connection.

[0010] In one embodiment, the detection system includes: a vibration sensor, two thermocouple sensors, an infrared thermal imager, and an electron microscope; The cover on the upper surface of the gearbox is a transparent observation cover; The vibration sensor is fixed to the gearbox housing and is connected to the control cabinet via signal transmission. The two thermocouple sensors are respectively embedded in the bodies of the first gear under test and the second gear under test, and the two thermocouple sensors are connected to the control cabinet for signal transmission. The infrared thermal imager is located above the first and second gears under test and is fixed on the transparent observation cover of the gearbox. The infrared thermal imager is also connected to the control cabinet via signal. The electron microscope is connected to the host computer via signal transmission.

[0011] In one embodiment, the control cabinet integrates an auxiliary protection system, which includes overload protection, over-temperature protection, insufficient lubricating oil protection, and emergency shutdown function.

[0012] In one embodiment, it further includes: The host computer processes and analyzes the collected detection data to obtain vibration spectrum diagrams, tooth surface morphology comparison diagrams, and fault assessment results. It also records experimental parameters and damage data to generate an aero-engine gear damage test report.

[0013] In one embodiment, the detection data includes: gear body temperature, transient temperature distribution on the tooth surface, vibration signal, and gear surface images and oil sample abrasive results collected after operation and shutdown.

[0014] In one embodiment, the data processing and analysis includes: The vibration signal is subjected to noise reduction, filtering, time-synchronized averaging, and segmented averaging according to the gear rotation cycle to obtain the processed vibration signal. Based on the processed vibration signal, peak value, root mean square value, and kurtosis are extracted to establish a damage feature set; The surface image of the gear is analyzed to extract parameters such as tooth surface roughness, wear amount, wear depth, and pitting.

[0015] The experimental setup for testing gear damage in aero-engines described above has the following beneficial effects: The operating condition simulation is realistic and reliable with strong adaptability: It can accurately reproduce the complex operating conditions of aero-engine gears at high speed (100 r / min - 6000 r / min), under load (0 kN - 50 kN), and with varying lubrication conditions (20℃-160℃ oil temperature, 0 L / min-3 L / min flow rate). It supports multiple speed switching, multiple loading modes, and multiple lubrication methods. The gear mounting base is compatible with aero-engine gears of different specifications and precisions, and it is convenient to periodically stop the machine to disassemble the gears for electron microscopy observation, solving the problems of poor adaptability, single operating condition simulation, and inconvenient observation of existing devices.

[0016] Comprehensive and high-precision detection: It integrates four major detection modules: vibration, temperature, tooth surface electron microscopy observation, and oil sample abrasive electron microscopy observation. It collects gear damage-related data from multiple angles and scales. The vibration signal acquisition frequency is no less than 100kHz, the electron microscopy observation accuracy can reach 0.1μm, and the temperature control accuracy is ±1℃. It can capture early and weak gear damage, and further assist in judging the wear type through oil sample abrasive observation. It comprehensively reflects the failure characteristics of gear wear and pitting, and solves the defects of insufficient detection dimensions and low accuracy of existing devices.

[0017] Easy to operate and safe and reliable: The device adopts a modular design, making gears easy to disassemble and assemble. Experimental parameters can be customized, and data acquisition, processing, and report generation are all automated. The periodic shutdown observation process is simple, greatly reducing the intensity of manual operation. It is equipped with a complete safety protection system, covering multiple protections such as overload, over-temperature, and insufficient lubrication, and supports long-term durability testing to ensure the safety of personnel and equipment during the experiment, while also ensuring the integrity of the observed samples. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the experimental setup for testing gear damage in an aero-engine, as shown in one embodiment. Figure 2 This is a system architecture block diagram of an experimental apparatus for testing gear damage in an aero-engine, as shown in one embodiment. Figure 3 This is a schematic diagram of vibration signal analysis in one embodiment; Figure 4 This is a schematic diagram of electron microscopy observation of the tooth surface in one embodiment. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] In one embodiment, such as Figure 1 As shown, an experimental apparatus for testing gear damage in an aero-engine is provided, comprising: a gearbox 5, a control cabinet 22, a host computer 23, a power system, a loading system, a lubricating oil temperature control system, and a detection system; The control cabinet 22 is connected to the host computer 23, the power system, the loading system, the lubricating oil temperature control system, and the detection system. The first test gear 20 is installed on the first gear shaft 18 of the power system and is located in the gearbox 5. The second test gear 21 is installed on the second gear shaft 19 of the loading system and is located in the gearbox 5. The first test gear 20 and the second test gear 21 mesh.

[0021] Among them, the gearbox 5 can be a split gearbox 5. As the core load-bearing component of the experimental device, the gearbox 5 houses the first test gear 20 and the second test gear 21, as well as the first gear shaft 18 and the second gear shaft 19, providing a closed operating space for the gear pair and integrating various sensor interfaces.

[0022] The host computer 23 sends control commands to the control cabinet 22, enabling the control cabinet 22 to control the operation of the power system, loading system, and lubricating oil temperature control system, and to control the detection system to collect detection signals.

[0023] The host computer 23 can be an industrial computer, which has dedicated analysis software installed or programmed and a data storage unit. The host computer 23 is used to write experimental programs, set parameters, monitor the experimental process in real time, process the collected data, and generate test reports.

[0024] The dedicated analysis software adopts a modular design and includes five major modules: data preprocessing, feature extraction, fault identification, life prediction, and report generation. The user interface is simple and supports custom parameter settings. It can automatically extract and analyze features from tooth surface images, abrasive grain images observed by electron microscope 24, and vibration signals collected by vibration sensor 1.

[0025] Among them, the control cabinet 22 can be a PLC control cabinet 22. The control cabinet 22 serves as the control core of the entire device, receiving instructions from the host computer 23, controlling the operation of components such as the motor 12, magnetic powder brake 10, and lubricating oil pump 13, and collecting various sensor data.

[0026] The control cabinet 22 integrates an auxiliary protection system, which includes overload protection, over-temperature protection, insufficient lubricating oil protection, and emergency shutdown function. When the load exceeds 120% of the rated value, the oil temperature exceeds 160℃, or the lubricating oil is insufficient, the system will automatically alarm and shut down. Both the experimental site and the PLC control cabinet 22 are equipped with an emergency shutdown button. Pressing the button will immediately cut off all power supply to ensure the safety of personnel and equipment. It also facilitates the disassembly of gears and collection of oil samples for observation under an electron microscope 24 after periodic shutdown.

[0027] In one embodiment, the power system includes: a motor 12, a first coupling 8a, a second coupling 8b, a third coupling 8c, a first gear shaft 18, a torque meter 9, and a first encoder 7a; The motor 12 is located on the right side of the first coupling 8a. The motor 12 is connected to one end of the first gear shaft 18 through the first coupling 8a. The torque meter 9 is located on the left side of the first coupling 8a and is connected to the first gear shaft 18. The second coupling 8b rigidly connects the first test gear 20 output from the gearbox 5 to the torque meter 9; The first encoder 7a is connected to the other end of the first gear shaft 18 via the third coupling 8c.

[0028] Among them, motor 12 serves as a power source, driving the first tested gear 20 to rotate, providing power for the entire experimental device.

[0029] The first encoder 7a is installed at the end of the first gear shaft 18 to accurately acquire the rotational speed and angular displacement signals of the gear, thereby achieving time synchronization and alignment of the vibration signals.

[0030] Among them, the first coupling 8a, the second coupling 8b and the third coupling 8c are used to connect the corresponding devices, transmit power and compensate for installation errors.

[0031] Among them, the torque meter 9 is connected in series in the power transmission chain to measure the torque value in real time during the gear transmission process, providing data for load analysis.

[0032] The first gear shaft 18 serves as the drive shaft and is driven to rotate by the motor 12.

[0033] Among them, the first test gear 20 is the driving gear, which is installed on the first gear shaft 18 and meshes with the second test gear 21 to transmit power.

[0034] Among them, the second test gear 21 is a driven gear, which is installed on the second gear shaft 19, meshes with the first test gear 20, and bears the load.

[0035] Among them, motor 12 is a high-precision AC servo motor 12 with a power of 4kW and a speed stability of ≤±0.1%. The coupling adopts a high torsional stiffness and low bending stiffness structure to reduce vibration transmission. Torque meter 9 has a measurement range of 0 Nm-100 Nm and a measurement accuracy of not less than ±0.1%FS, providing real-time feedback of gear transmission torque. The encoder is installed on the gear shaft end with a measurement accuracy of ≤0.1°, used to collect gear speed and angular displacement data, and assist in achieving synchronous alignment of vibration signals.

[0036] In one embodiment, the loading system includes: a magnetic powder brake 10, a second gear shaft 19, a heat pump 11, a fourth coupling 8d, a fifth coupling 8e, and a second encoder 7b. The cooling pump 11 is connected to the magnetic powder brake 10. The magnetic powder brake 10 is connected to one end of the second gear shaft 19 through the fourth coupling 8d. The second encoder 7b is connected to the other end of the second gear shaft 19 through the fifth coupling 8e.

[0037] The second encoder 7b is installed at the end of the second gear shaft 19 and is used to accurately acquire the speed and angular displacement signals of the gear to achieve time synchronization and alignment of the vibration signals.

[0038] Among them, the fourth coupling 8d and the fifth coupling 8e are used to connect the corresponding devices, transmit power and compensate for installation errors.

[0039] Among them, the magnetic powder brake 10 serves as the actuator of the loading system, and applies and controls the load on the second gear shaft 19 by adjusting the excitation current.

[0040] The cooling pump 11 is connected to the magnetic powder brake 10 to provide cooling oil flow and prevent the brake from failing due to overheating.

[0041] The second gear shaft 19 serves as the driven shaft, meshing with the first tested gear 20 for transmission, and is connected to the magnetic powder brake 10.

[0042] The magnetic powder brake 10 operates to achieve precise adjustment and stable loading of the load; the cooling pump 11 is linked with the magnetic powder brake 10 and adopts a forced circulation cooling method. The cooling medium is a special cooling oil with a flow rate of 10 L / min - 30 L / min, which ensures that the operating temperature of the magnetic powder brake 10 is maintained below 80℃ to avoid the braking force drift caused by high temperature.

[0043] In one embodiment, the lubricating oil temperature control system includes: a heating and cooling device 17, a temperature sensor 4, a lubricating oil tank 6, a lubricating oil pipe 14, a lubricating oil pump 13, and an electromagnetic flow control valve 16. The bottom of the lubricating oil tank 6 is provided with an oil sample collection interface 15. The heating and cooling device 17 is integrated into the lubricating oil tank 6. The oil inlet of the lubricating oil pump 13 is connected to the outlet of the lubricating oil tank 6 through the lubricating oil pipe 14. The oil outlet of the lubricating oil pump 13 delivers lubricating oil to the lubrication inlet in the gearbox 5 through the connecting lubricating oil pipe 14. The electromagnetic flow control valve 16 is installed between the oil outlet of the lubricating oil pump 13 and the gearbox 5. The lubricating oil in the gearbox 5 is delivered back to the lubricating oil tank 6 by connecting the lubricating oil pipe 14 between the lubricating oil outlet of the gearbox 5 and the lubricating oil tank 6. The temperature sensor 4 is installed in the lubricating oil tank 6 of the lubricating oil temperature control system and is connected to the heating and cooling device 17.

[0044] Among them, temperature sensor 4 is used to monitor the temperature of lubricating oil in real time and provide feedback signals to the lubricating oil temperature control system.

[0045] The lubricating oil tank 6 is used to store experimental lubricating oil. It has a built-in heating and cooling device 17 and a temperature sensor 4. It forms a circulating lubrication circuit with the lubricating oil pump 13 and the gearbox 5 through the lubricating oil pipe 14.

[0046] The lubricating oil pump 13 is installed at the outlet of the lubricating oil tank 6 to pressurize the lubricating oil and deliver it to the lubrication inlet of the gearbox 5, providing continuous lubrication and cooling for the gear meshing area.

[0047] Among them, the lubricating oil pipe 14 serves as a lubricating oil delivery channel, connecting the lubricating oil tank 6, the lubricating oil pump 13, the electromagnetic flow control valve 16, and the gearbox 5 to form a complete circulating oil circuit.

[0048] The oil sample collection interface 15 is located at the bottom of the lubricating oil tank 6 and is used to periodically collect lubricating oil samples for abrasive analysis to determine the wear condition of the gears.

[0049] The heating and cooling device 17 is integrated into the lubricating oil tank 6 and consists of an electric heating tube and a plate heat exchanger, which stabilizes the oil temperature at the target value set in the experiment.

[0050] Among them, the heating and cooling device 17 adopts a PID temperature control algorithm, which can quickly heat up to the target oil temperature and maintain it stably, adapting to the full range of temperature control requirements from 20℃ to 160℃; the temperature sensor 4 is used to monitor the temperature of the lubricating oil in real time and provide feedback signals for the lubricating oil temperature control system.

[0051] The electromagnetic flow control valve 16 is connected in series on the lubricating oil pipe 14 and is located between the lubricating oil pump 13 and the gearbox 5. It is used to precisely regulate and measure the flow rate of lubricating oil entering the gearbox 5.

[0052] In one embodiment, the detection system includes: a vibration sensor 1, two thermocouple sensors 3, an infrared thermal imager 2, and an electron microscope 24; Vibration sensor 1 is fixed to the housing of gearbox 5 and is connected to control cabinet 22 via signal. Two thermocouple sensors 3 are respectively embedded in the bodies of the first gear under test 20 and the second gear under test 21, and the two thermocouple sensors 3 are connected to the control cabinet 22 for signal transmission. The cover on the upper surface of the gearbox 5 is a transparent observation cover 25; the infrared thermal imager 2 is located above the first gear under test 20 and the second gear under test 21, and is fixed on the transparent observation cover 25 of the gearbox 5. The infrared thermal imager 2 is connected to the control cabinet 22 via signal. The electron microscope 24 is connected to the host computer 23 via signal transmission.

[0053] Among them, vibration sensor 1 can be a piezoelectric vibration sensor 1.

[0054] Vibration sensor 1 is fixed on the housing of gearbox 5 and is used to collect vibration signals during gear operation in real time, providing a data basis for subsequent fault diagnosis and damage analysis.

[0055] The infrared imager is fixed on the gearbox 5 and is aimed at the gear meshing area through the transparent observation cover 25. It is used for non-contact monitoring of the temperature distribution of the tooth surface and reflects the gear meshing state.

[0056] Two thermocouple sensors 3 are embedded in the bodies of the first test gear 20 and the second test gear 21, respectively, avoiding the gear meshing force area, and are used to collect the temperature of the gear body, which complements the data of the infrared imager for temperature monitoring.

[0057] Among them, the electron microscope 24 is used to periodically observe the microscopic morphology of the gear tooth surface and the abrasive characteristics in the oil sample, providing an intuitive basis for judging the damage type and assessing the severity.

[0058] The transparent observation cover 25 is installed on the top of the gearbox 5, providing an observation window for the infrared imager and facilitating the observation of the gear operation by the experimenters.

[0059] Among them, the piezoelectric vibration sensor 1 has a frequency range of 1 Hz - 25000Hz and a sensitivity of 100mV / g. It is installed on the side of the gearbox 5 housing and the shaft end to collect vibration signals from multiple directions. The infrared thermal imager 2 has a temperature resolution of ≤0.01℃ and collects the temperature distribution of the tooth surface through the transparent observation cover 25 of the gearbox 5. The electron microscope 24 has an adjustable magnification (100x-10000x) and can accurately observe the micro-morphology of the tooth surface and the abrasive characteristics in the oil sample, meeting the accuracy requirements of wear, pitting and abrasive analysis.

[0060] In one embodiment, the control cabinet 22 integrates an auxiliary protection system, which includes overload protection, over-temperature protection, insufficient lubricating oil protection, and emergency shutdown function.

[0061] The auxiliary protection system is integrated into the PLC control cabinet 22, including overload protection, over-temperature protection, insufficient lubricating oil protection, and emergency shutdown function. When the load exceeds 120% of the rated value, the oil temperature exceeds 160℃, or the lubricating oil is insufficient, the system will automatically alarm and shut down. Both the experimental site and the PLC control cabinet 22 are equipped with an emergency shutdown button. Pressing the button will immediately cut off all power supply to ensure the safety of personnel and equipment. It also facilitates the disassembly of gears and collection of oil samples for observation under an electron microscope 24 after periodic shutdown.

[0062] In one embodiment, the system further includes a host computer 23 that processes and analyzes the collected detection data to obtain a vibration spectrum diagram, a tooth surface morphology comparison diagram, and a fault assessment result, and records experimental parameters and damage data to form an aero-engine gear damage test report.

[0063] In one embodiment, the detection data includes: gear body temperature, transient temperature distribution on the tooth surface, vibration signal, and gear surface images and oil sample abrasive results collected after operation and shutdown.

[0064] In one embodiment, data processing and analysis includes: The vibration signal is processed by noise reduction, filtering, time-synchronized averaging, and segmented averaging according to the gear rotation cycle to obtain the processed vibration signal. The peak value, root mean square, and kurtosis are extracted from the processed vibration signal to establish a damage feature set. The gear surface image is analyzed to extract the tooth surface roughness, wear amount, wear depth, and pitting parameters.

[0065] In the process of processing vibration signals, the noise reduction algorithm adopts wavelet threshold noise reduction, and the threshold is adaptively adjusted according to the signal-to-noise ratio to effectively remove high-frequency noise; the filtering process adopts a bandpass filter with a frequency range of 1 Hz - 25000Hz to retain the frequency components related to gear damage; the time synchronization averaging process averages the vibration signal according to the gear rotation cycle based on the speed signal collected by the encoder, thereby enhancing the periodic signal and suppressing non-periodic noise.

[0066] In the image information processing, surface roughness Ra (i.e., tooth surface roughness), wear depth, wear amount, and pitting parameters are all extracted from gear surface images observed by electron microscope 24. The surface roughness Ra is measured in the range of 0.01μm - 10μm with a measurement accuracy of ≤0.1μm; the wear depth is measured in the range of 0μm - 100μm with an accuracy of ≤0.1μm; the wear amount is the area of ​​the gear that is worn; the maximum diameter of pitting is measured in the range of 0.1 mm - 10 mm. The number and area of ​​pitting can be automatically identified and counted from gear surface images observed by electron microscope 24, and the pitting density can be calculated. Furthermore, abrasive particles in oil samples can be observed by electron microscope 24, with a detection range of 1μm - 100μm. The number and concentration of abrasive particles in different size ranges can be counted, and the morphological characteristics and quality of abrasive particles can be analyzed to determine the damage type and degree.

[0067] In one embodiment, the experimental device for testing damage to aero-engine gears is still surrounded by an acrylic protective cover 26, which serves as a safety protection function.

[0068] It should be understood that the experimental setup for testing damage to aero-engine gears is adapted to the testing requirements of aero-engine gears, specifically as follows: The gear mounting bracket supports quick assembly and disassembly of aero-engine gear pairs with different modules (1 mm - 3 mm) and tooth counts (19-52 teeth), facilitating rapid gear removal after periodic shutdowns for observation under an electron microscope 24. All core components use standardized interfaces, supporting upgrades and replacements of sensors, electron microscopes 24, and other testing equipment, allowing for expansion of testing dimensions and functions according to actual testing needs. It is equipped with a dedicated oil sample collection interface 15, facilitating rapid collection of lubricating oil samples during periodic shutdowns for abrasive analysis in conjunction with the electron microscope 24.

[0069] The experimental setup for testing gear damage in this aero-engine employs a combination of parameters to describe and observe various states throughout the gear's entire lifecycle. An infrared thermal imager 2 monitors the transient temperature distribution of the gear; a thermocouple sensor 3 monitors the gear body temperature; a vibration sensor 1 monitors specific vibration signals generated by gear damage; and an electron microscope 24 periodically monitors the gear surface condition and abrasive particles in the lubricating oil. This information determines the damage type, area, and depth, and serves as the basis for classifying and labeling the collected temperature and vibration signals.

[0070] The experimental setup for testing gear damage in aero-engines integrates a computer control and information processing module. This setup features timed shutdown checks and active safety protection; it can collect and store experimental data, process vibration signals, and perform visual quantitative analysis of image information.

[0071] In one embodiment, such as Figure 2 As shown, a single-stage spur gear pair (module 2mm, number of teeth 19 / 52, accuracy JIS 4, material is low carbon steel JIS S45C) of a certain type of aero-engine is used as the test object. This gear pair is subjected to high-speed and heavy-load conditions for a long time and is prone to fatigue pitting and abrasive wear failure. Referring to the gear fatigue accelerated test method, the experimental device for aero-engine gear damage testing of this application is used to carry out the full life cycle fatigue pitting accelerated test of the gear. The core purpose is to simulate the damage evolution process of this type of gear in actual operation, capture the characteristic parameters of different damage stages, verify the working condition simulation capability, multi-dimensional detection accuracy and fault identification reliability of the device, and at the same time provide experimental data support for the optimization of the remaining life prediction model of this type of gear.

[0072] Preparations before the experiment in this embodiment: The experimental device for testing damage to aero-engine gears of this application was set up and the system calibration was completed. All core components (sensors, electron microscope 24, torque meter 9, etc.) were calibrated and qualified by a third-party metrology institution. The gear pair to be tested was pretreated by cleaning the oil stains on the tooth surface with acetone. The initial tooth surface condition was observed through electron microscope 24 (magnification of 5000x) to confirm that there was no initial damage and that it met the factory standards for aero-engine gears. Lubricating oil was prepared and the oil sample was ensured to be free of impurities. The functions of the auxiliary protection system were checked and the response reliability of protection mechanisms such as overload, over-temperature, and insufficient lubricating oil was verified to ensure that the experimental process was safe and controllable.

[0073] The experimental setup for testing gear damage in this aero-engine uses a PLC control cabinet 22 as the control core and an industrial computer 23 as the host computer scheduling unit. The power system, loading system, and lubricating oil temperature control system work together to construct a stable test condition. All components of the detection system synchronously acquire signals, and all data are uniformly transmitted, stored, and preprocessed to fully realize the data acquisition of the entire life cycle of gear damage.

[0074] First, during the equipment startup phase, motor 12 drives the gear pair via a coupling, torque meter 9 provides real-time feedback of transmission torque, and encoder collects speed and angular displacement signals, providing a reference for power parameter acquisition and signal synchronization. Magnetic powder brake 10 applies a set load, and cooling pump 11 provides synchronous cooling to ensure stable load output. Oil pump 13, electromagnetic flow control valve 16, and heating / cooling device 17 work together to stabilize lubricating oil temperature and flow at target values, providing a consistent operating environment for data acquisition. Once the operating conditions stabilize, PLC control cabinet 22 sends acquisition commands to each detection device, and all sensors and observation equipment start working synchronously.

[0075] During equipment operation, a large amount of data is collected in real time. Vibration sensor 1 is installed in the gearbox housing 5 and collects vibration signals at a frequency of 100kHz; embedded thermocouple sensor 3 collects the gear body temperature, and infrared thermal imager 2 collects the transient temperature distribution of the gear surface through the transparent observation cover 25; torque meter 9, encoder, and oil tank temperature sensor 4 synchronously upload operating parameters such as speed, torque, and oil temperature, and all data can be transmitted to the industrial computer in real time.

[0076] In addition, the device will automatically shut down according to a set cycle to periodically acquire microscope observation data. The PLC control cabinet 22 will periodically cut off the power supply. After the gear pair is disassembled from the gearbox 5, the electron microscope 24 can perform microscopic observation of the tooth surface and extract morphological data such as surface roughness, wear depth, and pitting parameters. At the same time, lubricating oil is extracted through the oil sample acquisition interface 15, and the electron microscope 24 observes the abrasive particle size, concentration, and morphology of the oil sample. The microscopic images and data are transmitted to the host computer 23 in real time for data processing.

[0077] The industrial computer will receive all the above data and images, assign a unified number to the files and align the timestamps, providing data support for subsequent fault identification, life prediction and report generation.

[0078] The steps for testing the first gear 20 and the second gear 21 are as follows: Step S1, assemble the gear pair to be tested: Drill holes on both sides of the tooth root of the spur gear to be tested from the aero-engine, insert thermocouple sensors 3 into the holes, seal them with silicone rubber, and transmit the lead wires to the data acquisition system of the control cabinet 22 through a slip ring. Install the gear pair to be tested from the aero-engine (i.e., the first test gear 20 and the second test gear 21) in the split gearbox 5, check the meshing clearance of the gear pair to be tested, and repeatedly adjust it to 0.2mm (within the standard range of 0.1mm-0.3mm), which meets the technical requirements for aero-engine gear assembly; according to the device system architecture, connect the control cabinet 22, power system, loading system, lubricating oil temperature control system, detection system and host computer 23, tighten the connecting bolts of each component with a torque wrench, check that the circuit wiring is firm, the lubricating oil interface is well sealed, and there is no lubrication. The system was checked for oil leakage and loose circuits. The device was started and run unloaded for 5 minutes. The motor 12, magnetic powder brake 10, and cooling pump 11 were tested to ensure smooth operation without abnormal noise or vibration. The stability of data acquisition from the vibration sensor 1, temperature sensor 4, two thermocouple sensors 3, infrared thermal imager 2, encoder, and torque meter 9 was checked to ensure that the vibration signal was free of noise, the temperature feedback was accurate, and the speed and torque data were synchronized in real time. After confirming that there were no abnormalities in each system, the unloaded operation was stopped, and the residual impurities inside the gearbox 5 were cleaned to prepare for the experimental condition setting stage.

[0079] Step S2, set the experimental operating parameters: set the target speed in the range of 100 r / min to 6000 r / min through the motor 12 of the power system; select the graded loading or fixed loading mode through the loading system, and apply a load in the range of 0 kN to 50 kN to accelerate the gear degradation process; set the lubricating oil temperature in the range of 20℃ to 160℃ and the lubricating oil flow rate in the range of 0 L / min to 3 L / min through the lubricating oil temperature control system, and select the splash or jet lubrication method.

[0080] Specifically: Referring to the actual operating conditions of the gears in this type of aero-engine (takeoff speed 2800 r / min - 3200 r / min, cruise speed 3000 r / min, load 15 kN - 40 kN, lubricating oil temperature 90℃ - 110℃), an experimental design approach based on load grading was adopted. Experimental parameters that closely resemble reality and accelerate damage evolution were set to ensure that the experimental results not only reproduce the actual damage mechanism but also shorten the experimental cycle. Through the vector control servo motor 12 of the power system, the target speed was set to 3000 r / min (corresponding to the medium-load operating speed of the aero-engine gears during the cruise phase), and the speed stability was controlled within ±0.1% to avoid speed fluctuations interfering with the gear damage evolution. Through the loading system, a graded loading mode was selected, setting the load gradient to 10 kN, 20 kN, 30 kN, and 40 kN. Each load level is maintained for 10 hours, with the gradient step size of the graded loading set at 10kN. This gradually increases the gear's stress strength, accelerates the gear's fatigue pitting degradation process, and reproduces the actual stress state of this type of gear from light load to heavy load. The lubricating oil temperature control system sets the oil temperature to 100℃ to simulate the typical oil temperature during normal gear operation, with a temperature control accuracy of ±1℃. The lubricating oil flow rate is 2L / min (within the adjustable range of 0L / min-3L / min). The jet lubrication method is selected to ensure that the lubricating oil is accurately sprayed to the gear meshing area through a special nozzle to form a uniform oil film, while simulating the actual lubrication environment of aero-engine gears.

[0081] Step S3, Data Acquisition: Turn on the vibration sensor 1, thermocouple sensor 3, infrared thermal imager 2, etc. of the detection system to simultaneously collect the gear body temperature, the transient temperature distribution of the tooth surface, and vibration signals. After the timed shutdown, collect the tooth surface roughness, wear amount, wear depth, and pitting parameters. The vibration signal acquisition frequency is not less than 100kHz, and the continuous acquisition time is set according to the experimental requirements.

[0082] Specifically: The vibration sensor 1, thermocouple sensor 3, and infrared thermal imager 2 of the detection system are activated. According to the detection accuracy requirements, the signal acquisition frequency of vibration sensor 1 is set to 100kHz, the sampling bit depth to 24 bits, and the continuous acquisition time to 40 hours (covering all graded loading stages). All acquired data is transmitted to the host computer 23 in real time and stored. A dedicated data storage unit is used for backup to prevent data loss. A periodic observation design based on the gear's full life cycle experiment is adopted, with a timed shutdown interval set at 10,000 gear cycles (within an adjustable range of 5,000-100,000 cycles). After each shutdown, following safety operating procedures, all power supplies are first turned off, and the gearbox 5 is allowed to cool to room temperature (to avoid high-temperature disassembly and damage to the gear samples). The gear sample was then disassembled, and 50 mL of lubricating oil was collected through the oil sample collection interface 15 on the oil tank. A scanning electron microscope 24 (5000x magnification) was used to observe the microstructure of the three marked tooth surfaces (tooth tip, tooth middle, and tooth root), focusing on recording the tooth surface roughness, wear depth, and the number and size of pitting pits. Simultaneously, the size, morphology, and concentration of abrasive particles in the oil sample were observed, and clear microscopic images of the tooth surface and oil sample abrasive particles were captured. All observation data and images were transmitted to the data processing system in real time and stored accordingly. After observation, acetone was used to clean the residual lubricating oil from the gear sample surface, the gear was reassembled, the meshing clearance was adjusted to 0.2 mm, and the device was restarted to enter the next stage of loading test, ensuring experimental continuity and data consistency.

[0083] Step S4, Data Processing and Analysis: The data processing system of the host computer 23 performs preprocessing such as noise reduction and filtering on the collected data; extracts statistical features such as peak value, root mean square, and kurtosis from the vibration signal; extracts steady-state temperature and fluctuation amplitude features from the temperature data; extracts surface roughness Ra, wear depth, number of pits, and maximum diameter features from the morphology data (i.e., gear surface image); and classifies and labels the corresponding vibration signals; and establishes a fault identification model by combining the SVM algorithm to determine the type, location, and severity of wear and pitting.

[0084] Specifically, the vibration signal is preprocessed and features such as peak value, root mean square, and kurtosis are extracted to establish a damage feature set; the steady-state temperature of the gear body and the temperature fluctuation range are extracted from the temperature data. If there are no obvious abnormalities, it indicates that the lubricating oil temperature control system is working stably and the oil temperature has no additional impact on the gear damage evolution; features such as surface roughness Ra, wear amount, wear depth, and pitting parameters are extracted from the results of electron microscopy observation of the gear surface (i.e., gear surface image); and the abrasive particle size, concentration, and morphology features are extracted from the results of electron microscopy observation of oil sample abrasive particles. The main concentration range of abrasive particle size, the change of concentration with increasing load, and the abrasive particle morphology are statistically analyzed.

[0085] Step S5: Generate a complete test report: The data processing system of the host computer 23 outputs vibration spectrum diagram, tooth surface morphology comparison diagram and fault assessment results, records experimental parameters and damage data, and generates an aero-engine gear damage test report.

[0086] A 4kW high-precision AC servo motor 12 is selected and connected to one end of the first gear shaft 18 via a first coupling 8a with high torsional stiffness and low bending stiffness. A torque meter 9 is connected in series between the motor 12 and a second coupling 8b, and a first encoder 7a is precisely installed on the other end of the first gear shaft 18. Post-assembly debugging shows that the rotational speed stability is controlled within ±0.08%, meeting the design requirement of ≤±0.1%. The torque meter 9 has a measurement range set to 0 Nm - 80 Nm, and the actual measurement accuracy reaches ±0.08%FS. The angular displacement measurement error of the first encoder 7a is 0.05°, less than the design threshold of ≤0.1°, effectively achieving synchronous alignment of vibration signals.

[0087] In this embodiment, the loading system is specifically applied as follows: the loading system connects the magnetic powder brake 10 to the second gear shaft 19, thereby increasing the load on the gear. The response time for load adjustment is 0.3s, which meets the requirements for precise adjustment. The cooling pump 11 operates in conjunction with the magnetic powder brake 10. The cooling oil flow rate is set to 20L / min. After running continuously for 30 minutes, the operating temperature of the magnetic powder brake 10 stabilizes at 62℃, which is far below the safety threshold of 80℃.

[0088] In the experimental setup for testing gear damage in this aero-engine, the lubricating oil temperature control system features a well-sealed lubricating oil tank 6, lubricating oil pump 13, and electromagnetic flow control valve 16, with no leakage. The lubricating oil heating and cooling device 17 uses a PID temperature control algorithm, setting a target oil temperature of 100℃. After the temperature stabilizes, the fluctuation range is ±0.8℃, meeting the control accuracy requirement of ±1℃. The data acquisition delay of the embedded thermocouple sensor 3 and the infrared thermal imager 2 is 8ms, enabling real-time monitoring of the gear surface temperature distribution.

[0089] The vibration sensor 1 in the detection system is fixed to the side of the gearbox 5 housing. After calibration, its sensitivity is 100mV / g, and its frequency response range covers 1 Hz - 25000Hz. The magnification of the electron microscope 24 is continuously adjustable in the range of 100-10000x. When observing the initial tooth surface, the surface roughness Ra measurement accuracy reaches 0.1μm, which meets the design standard. The lower limit of oil sample abrasive detection is 0.8μm, which meets the detection range requirement of 1μm - 100μm.

[0090] The data processing system utilizes dedicated analysis software on a computer, including modules for data preprocessing, feature extraction, fault identification, lifespan prediction, and report generation. During the experiment, the software can interface with devices such as vibration sensor 1 and electron microscope 24 to automatically acquire and store tooth surface images, abrasive grain images, and vibration signals.

[0091] When the auxiliary protection system is working, if the simulated load exceeds 120% (60kN) of the rated value, the system will automatically alarm and stop within 0.2s; when the simulated oil temperature rises to 160℃, the protection mechanism will be triggered immediately; when the lubricating oil is insufficient, the liquid level monitoring module will respond quickly and cut off the power supply; after the emergency stop button at the test site and PLC control cabinet 22 is pressed, all power supplies will be cut off instantly, and all protection functions will be verified to be effective.

[0092] The data preprocessing and feature extraction are implemented as follows: When processing vibration signals, wavelet threshold denoising algorithm is used for noise reduction; time-synchronous averaging is based on the speed signal acquired by the encoder, and is averaged in segments according to the gear rotation period (0.02s) to suppress non-periodic noise. Then, statistical features such as peak value, root mean square, and kurtosis are extracted. A schematic diagram of vibration signal analysis is shown below. Figure 3 As shown.

[0093] When performing quantitative analysis on image information, the surface roughness Ra is measured in the range of 0.01 μm - 8 μm; the wear depth is measured in the range of 0 μm - 90 μm; and the maximum diameter of pitting is measured in the range of 0.1 mm - 8 mm. The number and area of ​​pitting are automatically identified by observing the images with an electron microscope, and the pitting density is calculated. A schematic diagram of electron microscope observation of tooth surfaces is shown below. Figure 3 As shown.

[0094] In this study, abrasive particles in the oil samples were measured in the range of 1 μm to 90 μm. The number and concentration of abrasive particles in different size ranges were statistically analyzed, and the damage type was determined by analyzing the morphological characteristics of the abrasive particles. When the abrasive particles were mainly irregular blocky, smooth-surfaced, and fatigue-cracked at the edges, they were identified as fatigue pitting of the gears. When larger, torn or flaky adhesive abrasive particles with traces of plastic deformation on the surface appeared, or when long, sharp-edged cutting abrasive particles appeared, they were identified as gear wear.

[0095] The overall adaptability of the device is specifically reflected in this embodiment as follows: The gear mounting base successfully enables rapid assembly and disassembly of the gear pair of this type of aero-engine with a module of 2mm and 19 / 52 teeth. All core components adopt standardized interfaces. During the experiment, a higher-precision infrared thermal imager 2 was replaced. The replacement process was simple and did not require modification of the main structure of the device.

[0096] Multi-parameter cross-observation was conducted in the experiment. Infrared temperature sensor 4 monitored the transient temperature distribution of the gear surface in real time, thermocouple sensor 3 collected the gear body temperature, vibration sensor 1 captured damage-related vibration signals, and electron microscope 24 periodically observed the gear surface condition and lubricating oil abrasive particles. Through multi-parameter cross-analysis, the damage evolution law of this type of gear at different load stages was clarified, providing a reliable basis for the classification and labeling of vibration signals and temperature data.

[0097] When using computer control and information processing, the timed shutdown interval is set to 10,000 gear cycles, and the device automatically executes the shutdown procedure; experimental data is stored in real time in a dedicated storage unit, supporting data traceability; the computer is used for vibration signal processing and image information visual quantitative analysis, which is efficient and accurate, providing comprehensive data support for fault identification and life prediction.

[0098] The aforementioned experimental setup for testing gear damage in aero-engines also features intelligent data processing and accurate identification: it employs professional preprocessing algorithms to improve data quality, extracts multi-dimensional fault features, and combines machine learning algorithms to establish a fault identification model. This model can accurately determine the type, location, and severity of wear and pitting, while also predicting remaining service life. The identification accuracy rate is no less than 90%, and the wear depth prediction error is ≤5%, providing a scientific basis for the diagnosis of gear faults in aero-engines.

[0099] It should be noted that the equipment structure and accompanying drawings of this application mainly describe the principle of this application. The setting of the power mechanism, power supply components, control components and data processing program of the device is not fully described. However, under the premise that those skilled in the art understand the principle of the above application, the specific details of its power mechanism, power supply components, control components and data processing program can be clearly understood. The control method of the application document is to control the motor 12, magnetic powder brake 10, lubricating oil pump 13 and cooling pump 11 in the experimental platform by inputting control signals from the computer to the PLC control cabinet 22. The control circuit and data processing program can be implemented by those skilled in the art through simple programming. The standard parts used can all be purchased from the market, and can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets and welding that are mature in the prior art. The machinery, parts and equipment adopt conventional models in the prior art, and the structure and principle of the components known to those skilled in the art can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0100] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An experimental apparatus for testing gear damage in aero-engines, characterized in that, The device includes: a gearbox, a control cabinet, a host computer, a power system, a loading system, a lubricating oil temperature control system, and a detection system; The control cabinet is connected to the host computer, power system, loading system, lubricating oil temperature control system, and detection system for signal transmission. The first test gear is mounted on the first gear shaft of the power system and located inside the gearbox; the second test gear is mounted on the second gear shaft of the loading system and located inside the gearbox; the first test gear meshes with the second test gear. The host computer sends control commands to the control cabinet, which then controls the operation of the power system, the loading system, and the lubricating oil temperature control system, and controls the detection system to collect detection signals.

2. The experimental apparatus for testing gear damage in aero-engines according to claim 1, characterized in that, The power system includes: a motor, a first coupling, a second coupling, a third coupling, a first gear shaft, a torque meter, and a first encoder; The motor is located on the right side of the first coupling, and the motor is connected to one end of the first gear shaft through the first coupling. The torque meter is located on the left side of the first coupling and connected to the first gear shaft. The second coupling rigidly connects the first test gear output from the gearbox to the torque meter; The first encoder is connected to the other end of the first gear shaft via the third coupling.

3. The experimental apparatus for testing gear damage in aero-engines according to claim 1, characterized in that, The loading system includes: a magnetic powder brake, a second gear shaft, a cooling pump, a fourth coupling, a fifth coupling, and a second encoder; The cooling pump is connected to the magnetic powder brake, which is connected to one end of the second gear shaft via a fourth coupling. The second encoder is connected to the other end of the second gear shaft via a fifth coupling.

4. The experimental apparatus for testing gear damage in aero-engines according to claim 1, characterized in that, The lubricating oil temperature control system includes: a heating and cooling device, a temperature sensor, a lubricating oil tank, a lubricating oil pipe, a lubricating oil pump, and an electromagnetic flow control valve; The bottom of the lubricating oil tank is provided with an oil sample collection interface. The heating and cooling device is integrated into the lubricating oil tank. The oil inlet of the lubricating oil pump is connected to the outlet of the lubricating oil tank through the lubricating oil pipe. The oil outlet of the lubricating oil pump delivers lubricating oil to the lubrication inlet in the gearbox through the lubricating oil pipe. The electromagnetic flow control valve is installed between the oil outlet of the lubricating oil pump and the gearbox. By connecting an oil pipe between the lubricating oil outlet of the gearbox and the lubricating oil tank, the lubricating oil in the gearbox is transported back to the lubricating oil tank; The temperature sensor is installed in the lubricating oil tank of the lubricating oil temperature control system, and the temperature sensor is connected to the heating and cooling device via a signal connection.

5. The experimental apparatus for testing gear damage in aero-engines according to claim 1, characterized in that, The detection system includes: a vibration sensor, two thermocouple sensors, an infrared thermal imager, and an electron microscope; The cover on the upper surface of the gearbox is a transparent observation cover; The vibration sensor is fixed to the gearbox housing and is connected to the control cabinet via a signal connection. The two thermocouple sensors are respectively embedded in the bodies of the first gear under test and the second gear under test, and the two thermocouple sensors are connected to the control cabinet for signal transmission. The infrared thermal imager is located above the first and second gears under test and is fixed on the transparent observation cover of the gearbox. The infrared thermal imager is also connected to the control cabinet via signal. The electron microscope is connected to the host computer via signal transmission.

6. The experimental apparatus for testing gear damage in aero-engines according to claim 1, characterized in that, The control cabinet integrates an auxiliary protection system, which includes overload protection, over-temperature protection, insufficient lubricating oil protection, and emergency shutdown function.

7. The experimental apparatus for testing gear damage in aero-engines according to claim 1, characterized in that, Also includes: The host computer processes and analyzes the collected detection data to obtain vibration spectrum diagrams, tooth surface morphology comparison diagrams, and fault assessment results. It also records experimental parameters and damage data to generate an aero-engine gear damage test report.

8. The experimental apparatus for testing gear damage in aero-engines according to claim 7, characterized in that, The detection data includes: gear body temperature, transient temperature distribution on the tooth surface, vibration signal, and gear surface images and oil sample abrasive results collected after operation and shutdown.

9. The experimental apparatus for testing gear damage in aero-engines according to claim 8, characterized in that, The data processing and analysis include: The vibration signal is subjected to noise reduction, filtering, time-synchronized averaging, and segmented averaging according to the gear rotation cycle to obtain the processed vibration signal. Based on the processed vibration signal, peak value, root mean square value and kurtosis are extracted to establish a damage feature set; The surface image of the gear is analyzed to extract parameters such as tooth surface roughness, wear amount, wear depth, and pitting.

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