Search

A herringbone gear transmission system with star gear train is taken as the research object. In order to find the cause of system resonance， a modal-analyzing 3D finite element model is established to analyze the modal characteristics of herringbone gear transmission system of star gear train. Firstly， according to the experimental results of star gear train， the resonance caused by rotational frequency excitation and meshing frequency excitation is the main part of the vibration amplitude of the system. According to this phenomenon， a 3D finite element model is established based on the meshing stiffness matrix to analyze the modal characteristics of the system. The results show that the rotational frequency resonance mode and meshing frequency resonance mode obtained by simulation are uniquely corresponding to the experiment data， and the meshing frequency resonance mode is mainly represented by the fifth pitch diameter vibration mode of the inner gear and the torsional vibration mode of the coupled gear pair. This finite element model provides a valuable reference method for resonance prediction and resonance cause analysis of herringbone gear transmission system with star gear train.

Taking a herringbone gear transmission system with star gear train as the research object and based on the finite node method，a system-level dynamics model considering shaft-bearing-rigid rotor and the meshing of gears is established. The dynamic characteristics of the system are analyzed based on the RMS of vibration velocity at the bearings with the rotation speeds. Then the theoretical analysis results are compared with the experimental data to verify the reliability of the proposed model. After that，based on the analysis of vibration characteristics and modal characteristics of the gear system，resonance localization and resonance cause analysis are carried out. The results show that the theoretical analysis is in good agreement with experimental results. This study provides a valuable reference method for resonance prediction and resonance cause analysis of herringbone gear transmission system of star gear train.

A herringbone gear transmission system is taken as the research object. A method of gear system-level modeling and simulation analysis is proposed. Based on the finite element node method，a dynamic model considering rigid rotor-shaft-bearing and the meshing of gears is established. Then the resonance speed of the system is analyzed and the result is compared with the experimental data to verify the reliability and limitations of the finite element node model. Then a 3D finite element model used for natural frequency calculation and vibration mode analysis is established. The modeling of gear meshing is used in finite element node method. Finally，combined with the modal analysis and response analysis，the theoretical analysis is compared with the experimental data. And the cause of experimental resonance is determined and resonance localization is realized，which provides direction for decreasing the vibration amplitude and avoiding the vibration.

The fan-driven gearbox is characterized by complex structure and difficult system dynamics analysis. The accuracy of the component level model is verified through the modal analysis and the percussion modal test of the gearbox component. Then the rationality of the subsystem structure analysis is verified through the comparative analysis of the dynamic response analysis and performance test of the external meshing subsystem. Finally， through the mode synthesis method， each subsystem is unified into the internal meshing system for dynamic response calculation， and it is analyzed and verified with the test data. The key points of analysis and verification of each part are clarified and iterated step by step. A set of system-level analysis methods for theoretical analysis and test verification from component level to subsystem level and then to system level are established， so as to provide guidance and help for the parametric sensitivity analysis and modal identification of complex systems in the future.

According to the phenomenon of the external meshing herringbone teeth test of fan drive gearbox, based on the knowledge of dynamics analysis and failure theory, a set of method for purifying and filtering axis trajectory is established. The failure type is determined by comparing the variation trend of the purified filter axis trajectory diagram and the vibration data. The problem can be detected earlier and serious accidents can be avoided by the purified filter axis trajectory.