Dynamic Characteristics Of Planetary Gear System Based On Inctrmental Harmonic Balance Method

As an important mechanism to transmit motion and force, planetary gear system has been widely used as the main structure of the aircraft engines and mining machinery, which has unique structural features:light weight, small volume, compact in structure and smooth in work, most notably its power split when transmit force and its identical horizontal line between input and output shaft. While, the complexity of structure and working condition of planetary gear system and the problem of vibration and noise affect working accuracy, transferring efficiency and operating life. Therefore, it is significant to research on dynamic characteristics of planetary gear system and the dynamic response characteristics to reduce the vibration and noice, promote the development of the aviation industry of our country.The paper mainly concerns the dynamic characteristics of planetary gear system, and its dynamic response characteristics are analyzed based on IHB method and Newmark-β method; in addition, the dynamic model of planetary gear system from simply to complicate are established to investigate its characteristics and research on the influence of the time-varying mesh stiffness and error excitation on the three kinds of planetary gear system. The main research works are as follows:Firstly, this research focuses on single-layer planetary gear system, single-carrier compound planetary gear system and double-carrier compound planetary gear system as the study object. By means of Newton second law and Lagrange equation, motion and mechanical analysis were carried out to three kinds of planetary gear models, in order to set up the differential equation of torsional vibration and found all matrixes with detailed derivations and results. On this basis, conbining the knowledge of linear algebra, this research emphatically analyzes the relationship between the relative meshing displacements of each gear, simplifying semi-positive-definite torsional system and forming an uncomplicated, convenient and high suitability method to transform semi-positive-definite system into positive-definite system. Secondly, with gear clearance considered, this research established single-layer planetary gear dynamic model and got its dynamic characteristics. The results show that the phenomenon of amplitude jumping is much more obvious with the increasing of gear clearance. And when gear clearance is to a certain extent, hysteresis loop appears. But when gear clearance continues increasing, hysteresis loop decreases and disappreases, at the same time, amplitude jumping gradually weakens and vanishs.Finally, this research studied the timeliness and accuracy of the method of positive define. With the compare of computation durance of steady-state response and amplitude frequence response curve, IHB method contains greatly computational effiency. It also shows that the method of positive define possesses practicality and necessity.