Dynamic Modeling for Spur Planetary Gear Transmission with Flexible Ring Gear

2009 ◽  
Vol 45 (12) ◽  
pp. 29 ◽  
Author(s):  
Jun ZHANG
Keyword(s):  
Dynamic Modeling ◽  
Planetary Gear ◽  
Gear Transmission ◽  
Ring Gear ◽  
Flexible Ring

Parametric Instability of Planetary Gear Transmission Mounted on Discrete Support Struts With Minimum Ring Gear Rim Thickness Design

2018 ◽  
Author(s):  
Peng Guan ◽  
Hans DeSmidt
Keyword(s):  
Parametric Instability ◽  
Planetary Gear ◽  
Gear Transmission ◽  
Ring Gear ◽  
Mesh Stiffness ◽  
Gear Mesh ◽  
Stiffness Variation ◽  
Parametric Instabilities ◽  
Gear Mesh Stiffness ◽  
Flexible Ring

This research explores parametric instabilities of the PGT driveline system and a stability-based method for ring gear rim thickness design. Parametric excitation of a planetary gear transmission (PGT) driveline system arises from two sources: 1) gear mesh stiffness variation, 2) Interaction between moving planets, flexible ring gear and boundary struts. Many researchers have studied the parametric instability of planetary gear transmissions due to gear mesh stiffness variation, however, the effect of interaction between moving planets, flexible ring and discrete boundary struts on parametric instabilities has not been fully studied before. Especially, for sufficiently thin ring gears, this kind of effect becomes even more significant. To illustrate the novel PGT rim design proposal, firstly, a structural dynamics model of a complete PGT driveline system with elastic ring gear supported by discrete boundary struts is established. Secondly, by applying Floquet method, the parametric instability behavior due to the second parametric excitation source is fully investigated. Lastly, the design guidelines for planetary gear transmission ring gear rim thickness are proposed based on system stability from a dynamical viewpoint. The analysis and results provide new and important insights into dynamics and design of lightweight planetary gear transmission ring gear rim.

A Discrete Lumped-Parameter Dynamic Model for a Planetary Gear Set with Flexible Ring Gear

2011 ◽  
Vol 86 ◽  
pp. 756-761 ◽  
Author(s):  
Jun Zhang ◽  
Yi Min Song ◽  
Jin You Xu
Keyword(s):  
Individual Component ◽  
Natural Frequencies ◽  
Equations Of Motion ◽  
Planetary Gear ◽  
Lumped Parameter Model ◽  
Vibration Modes ◽  
Ring Gear ◽  
Lumped Parameter ◽  
Planetary Gear System ◽  
Flexible Ring

A discrete lumped-parameter model for a general planetary gear set is proposed, which models the continuous flexible ring gear as discrete rigid ring gear segments connected with each other through virtual springs. The ring-planet mesh is analyzed to derive equations of motion of ring segments and planet. By assembling equations of motion of each individual component, the governing equations of planetary gear system are obtained. The solution for eigenvalue problem yields to natural frequencies and corresponding vibration modes. The simulations of example system reveal that the ring gear flexibility decreases system lower natural frequencies and the vibration modes can be classified into rotational, translational, planet and ring modes.

Dynamic Analysis of Hybrid Gear Trains With Flexible Ring Gear Rim

2017 ◽  
Author(s):  
Xiangyang Xu ◽  
Junbin Lai ◽  
Yanfang Liu
Keyword(s):  
Dynamic Behavior ◽  
Planetary Gear ◽  
Transmission Error ◽  
Helical Gear ◽  
Gear Train ◽  
Gear Pair ◽  
Ring Gear ◽  
Gear Trains ◽  
Helical Gear Pair ◽  
Flexible Ring

In this paper, the dynamic behavior of a hybrid gear train (HGT), consists of a single-stage helical planetary gear set and a helical gear pair, is analyzed. A ring gear rim is connected with an internal gear in a helical planetary gear set and an external gear in a helical gear pair. Power flows from the helical gear pair to the helical planetary gear set. Therefore, loads in the external gear would cause additional axial force and radial force, which would lead to unexpected moment and force. As a result, deflections of ring gear rim must be taken into consideration. Under this condition, a three-dimensional dynamic model of a HGT with flexible ring gear rim is developed, in which six degrees of freedom including three translational motions and three rotational motions are employed. Coupling effects of the bearing support stiffness, gear mesh stiffness and time-varying transmission error are taken into consideration. The model also takes flexible supporting shafts and planet carrier into consideration by using finite element method. Then, the equations of motion in matrix form are established and solved to predict the forced vibration response due to the transmission error excitations. Subsequently, effects of positions of the helical gear pair relative to the planetary gear set and the thickness of ring gear rim on dynamic behavior of the HGT are discussed. The results show that the proposed model is potential and can be used to guide the design of hybrid gear trains.

Coupling effects of manufacturing error and flexible ring gear rim on dynamic features of planetary gear

2021 ◽  
pp. 095440622098336
Author(s):  
Zheng Cao ◽  
Meng Rao
Keyword(s):  
Planetary Gear ◽  
Gear Train ◽  
Influence Coefficient ◽  
Ring Gear ◽  
Dynamic Features ◽  
Coupling Effects ◽  
Manufacturing Error ◽  
Manufacturing Errors ◽  
Potential Energy Method ◽  
Flexible Ring

Manufacturing errors widely exist in and deteriorate the dynamic property of planetary gear train (PGT). To solve this problem, the ring gear is often designed with a thin rim to compensate for the effects of manufacturing errors via the elastic deflections of the rim. Existing dynamic models of the PGT only consider the effects of either the elasticity of the rim of the ring gear or the manufacturing errors. The coupling effects of manufacturing errors and the flexible ring gear are ignored. To understand the dynamic behaviors of the PGT better, a dynamic model of the PGT coupled with typical manufacturing error and flexible ring gear is developed in this study. The tooth contact analysis of the ring-planet mesh, which is calculated based on the potential energy method and uniformly curved Timoshenko beam theory, is studied using the influence coefficient method. A numerical algorithm is proposed to solve the integrated dynamic equations of the PGT. Calculated results show that the dynamic features of the PGT are complex, and the load sharing characteristic is improved when the flexible ring gear is incorporated.

A Gear Load Distribution Model for a Planetary Gear Set With a Flexible Ring Gear Having External Splines

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Yong Hu ◽  
David Talbot ◽  
Ahmet Kahraman
Keyword(s):  
Load Distribution ◽  
Planetary Gear ◽  
System Level ◽  
Distribution Model ◽  
Ring Gear ◽  
Baseline Model ◽  
Gear Mesh ◽  
Load Distributions ◽  
Planetary Gear Sets ◽  
Flexible Ring

In order to accurately predict ring gear deformations and to investigate the effects of ring gear flexibility on quasi-static behaviors of planetary gear sets, a complete load distribution model of planetary gear sets having flexible ring gears will be formulated here based on the baseline model proposed by the same authors (Hu, Y., Talbot, D., and Kahraman, A., 2018, “A Load Distribution Model for Planetary Gear Sets,” ASME J. Mech. Des., 140(5), p. 053302). Direct comparisons to published experiments are provided to assess the accuracy of the proposed load distribution methodology. Example analyses with flexible ring gear rims are performed indicating that ring gear flexibility could influence gear mesh-level and planetary gear set system-level behaviors. Influence of spline supporting a ring gear is also investigated revealing that positions of planet branches with respect to external splines could influence ring deflections and resultant gear mesh load distributions.

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