A Shahabi - Department of Mechanical Engineering, University of Sistan and Baluchestan, Zahedan , Iran
A.H Kazemian - Department of Mechanical Engineering, University of Sistan and Baluchestan, Zahedan , Iran

In industry applications, planetary gear systems are widely used in power transmission systems. In planetary gears, dynamic loads, noise and reduction the structural life are produced by system vibrations. For gear transmission systems, the parametric excitation which introduced by the periodically time–varying mesh stiffness of each gear oscillation is the main source of vibration. Generally, there are two methods to evaluate the gear mesh stiffnesses, the finite element method and the analytical method. In this wok, the periodically time–varying mesh stiffness of planetary gears is investigated. The influence of pressure angles on mesh stiffness of meshing gears is shown and the dynamic model of planetary gear sets is studied. When planets of the single–stage spur planetary gear system are meshed by new planets, the system is converted to special type of system with meshed planets. Vibration for geometrical structures (symmetric and anti–symmetric) of planetary system with meshed planets is investigated. Mesh stiffness of meshing gears by estimation function is obtained and numerical results of natural frequencies and vibration modes are derived.

Planetary gear, Vibration, Time–varying mesh stiffness, Dynamic Model