Dynamic Analysis of a Planetary Gear System

Abstract

Abstract Noise reduction in geared systems is usually achieved by minimizing transmission error or by changing the gear train’s dynamic response. While considerable research has been directed in the past to understanding and controlling the transmission error, the same can not be said of the system dynamic response. Recent efforts at modifying the dynamic response to reduce the sensitivity to transmission error have proven to be very rewarding for parallel shaft gearing applications. In this paper, these efforts are extended to planetary gear set applications. A major difference between planetary gear sets and parallel shaft gears is that in planetary gear sets many gear meshes carry load instead of just one. This feature poses a modeling problem as to how to combine responses due to transmission errors at each loaded mesh to determine the total response. A method is proposed in this paper in which transmission errors at different gear meshes are combined into net vertical, net lateral and net tangential transmission errors. A methodology for computing dynamic mesh force response due to these net transmission errors and for identifying critical components that control the gear train system dynamics is presented. These techniques are useful in understanding the effects of system dynamics on gear noise and in developing quiet gear design. To demonstrate the salient features of the proposed method, an example analysis of a transmission with a planetary gear set is presented.