Modelling and Simulation of Frequency Response on Input shaft/carrier of a Planetary Gear Train under the Influence of Vibration

E.M Etuk,R.S Ebhojiaye,K.R Ekanem

doi:10.4314/jasem.v25i4.16

Abstract

The transmission of motion from one gear to the other in a planetary gear train usually result in unwanted conditions such as vibration due to poor gear assembly, high contact forces, high rotation speeds etc. The vibrating effect of the gear can result in higher or lower frequency response which may damage the gear or offer safe working condition. Using SOLIDWORKS 2018 version for the modelling, SimulationXpress was used to conduct frequency analysis on input shaft/carrier of a planetary gear train to understand its behaviour at different mode shapes during vibration. Results obtain from the input shaft/carrier frequency analysis showed natural frequency values of 1922.4Hz, 1922.8Hz, 2101Hz, 2183.1Hz and 2185.3Hz for mode shape 1-5. Geometry of the input shaft/carrier appeared differently at each mode number, resulting in frequency responses characterised by different modal shapes. This also led to gradual increase in the natural frequency of the input shaft/carrier at increasing mode no, consequently causing deflection on the mode shapes of the input shaft/carrier model. Hence, vibration should be reduced to the lowest limit of tolerance for minimum deflections and longevity of the input shaft/carrier and planetary gear components.

Highlights

Planetary gears known as epicyclic gears are widely used for the transmission of power in various fields of application such as aerospace, wind turbines, automotive, marine etc
The vibrating planetary gear as it undergoes rotary motion translates the vibrating effect to the input shaft/carrier and other parts of the gear. This relates to the frequency/amplitude on the input shaft resulting from vibration of the planetary gear train during each rotation cycle
As the input shaft is disturbed from its uniform rotary motion, it tends to vibrate at certain frequencies known as natural or resonant frequencies which is the frequency is the frequency at which a body vibrates when excited by a force (EfeOnoneme et al, 2018)

Summary

Introduction

Planetary gears known as epicyclic gears are widely used for the transmission of power in various fields of application such as aerospace, wind turbines, automotive, marine etc. On the other hand, when the gears are not compact, it is likely to operate with geometrical errors or interference, vibration (due to high natural frequencies) and sound (noise) This may result in the rotational motion of the gear being transmitted imperfectly due to the presence of vibration, wear, deflection and friction between the meshing gear teeth (Cooley and Parker, 2014; Etuk et al, 2019). This may subject the gear shaft to loading conditions such as torsion, bending, and sometimes axial loading, thereby, affecting the transmission of power or torque and hampering the longevity and in-service performance of the gear (Loewenthal, 1984; Childs, 2014). The frequency response of input shaft/carrier in 3-stage planetary gear train under the influence of vibration was modelled and simulated in order to compute the excitation frequency resulting from each mode shape

Methods

Results

Conclusion