7/25/2019 PTGC 2011 Abstract

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DETC2011/PTG-

PLANETARY GEAR MODAL PROPERTIES AND DYNAMIC RESPONSE:EXPERIMENTS AND ANALYTICAL SIMULATION

Tristan M. Ericson,Graduate ResearcherDynamics and Vibrations Laboratory

Department of Mechanical and Aerospace EngineeringOhio State University, Columbus, OH 43210

Tel: 614-292-9029, Fax: 614-292-3163ericson.15@osu.edu.edu, WWW: http://www.mecheng.osu.edu/vibrations/

Robert G. Parker,Distinguished Professor ChairOhio State University

State Key Lab for Mechanical Systems and VibrationUniversity of Michigan-Shanghai Jiao Tong University Joint Institute

Shanghai Jiao Tong University, Shanghai, Chinaparker.242@osu.edu

Planetary gear vibration is a major source of noise and may lead to fatigue-inducedfailures in bearings or other drivetrain components. Gear designers use mathematical mod-els to analyze potential designs, but these models remain unverified by controlled experi-ments that demonstrate the independent motions of planetary gear components. This paperpresents experiments that completely characterize the dynamic behavior of a planetary gearby modal testing and spinning tests under representative operating conditions. Both exper-imental methods are used to measure the natural frequencies, modes, and dynamic responseof the gear. Results are compared to a lumped parameter model with high accuracy in mostcases.

This study focuses on the independent motion of each planetary component. Custom-made fixtures provide room for twenty-one accelerometers mounted directly to individualgear bodies to measure the actual motion of each component. Specialized data processingtechniques are used to calculate the rotational and translational accelerations of the carrier,sun gear, and two of five planets on the rotating carrier reference frame. Order tracking isused to separate the response at each harmonic of mesh frequency in spinning tests.

The experimental results are directly compared to the predictions of a lumped parametermodel previously presented in the research literature. Without tuning the model parameters,modal tests confirm all natural frequencies predicted in the model; twelve of fifteen agreewithin 5%. Dynamic responseincluding vibration amplitudeis also confirmed across awide frequency range in each gear component. Spinning tests further confirm many ofthe natural frequencies that the model predicts. The existence of rotational, translational,and planet mode types presented in published analytical research is verified experimentallyby both testing methods. The separation (decoupling) of low-frequency shaft modes andhigh-frequency tooth deflection modes is demonstrated in the experiments and the model.

Keywords: planetary, gear, dynamics, vibration, modal testing.

Copyright c 2011 by ASME