Internal Gear Strains and Load Sharing in Planetary Transmissions: Model and Experiments

Abstract

This paper presents results of a comprehensive experimental and theoretical study to determine the influence of certain key factors in planetary transmissions on gear stresses and planetary load sharing. A series of tests are conducted on a family of planetary gear sets, and strains are recorded at various locations on the outer diameter and gear tooth fillet of the ring gear. Pinion position errors are introduced as a representative key manufacturing tolerance, and the resultant changes in the planetary behavior are observed. The experimental data are compared to the predictions of a state-of-the-art multibody contact analysis model—Gear System Analysis Modules (GSAM). This model is capable of including the influences of a number of system-level variables and quantifying their impact on gear strains. The model predictions are shown to compare well with the measured strain at the ring gear outer diameter and tooth fillet. GSAM predictions of planet load sharing are then used to quantify the influence of tangential pinhole position errors on three-, four-, five-, and six-planet test gear sets. These predictions also agree well with the planet load sharing experiments presented in a companion paper.

Dynamic load sharing characteristics and sun gear radial orbits of double-row planetary gear train

“…They classified the gear set errors into three categories based on the ways in which the errors affected planet load sharing. SINGH et al [8] analyzed the internal strains and load sharing in planetary transmissions theoretically and experimentally. LIGATA et al [9] did further work along the lines of the study of KAHRAMAN [5], but added the number of planets and torque as parametric variables in their experiment study and got reasonable agreement with the theory.…”

Dynamic Behaviour of Back to Back Planetary Gear in Run Up and Run Down Transient Regimes

“…Ligata et al [3] used back-to-back planetary gear to study the impact of certain types of manufacturing errors on gear stresses and the planet load sharing between n-planet (n 3 6). Using multi-stage planetary gears, Singh et al [4] presented an experimental and theoretical study of the same gearbox in order to determine the influence of certain key factors in planetary transmissions on gear stresses and planetary load sharing. Boyd [5] expand the planetary gear dynamics program to add the option of evaluating the tooth pair dynamics for two planetary gear stages mounted back-to-back with peripheral components.…”

Research on multiple-split load sharing of two-stage star gearing system in consideration of displacement compatibility

“…Scholars from both home and abroad have been constantly exploring and studying power-split gearing system load sharing characteristics, and the research findings are as follows. Hidaka [11,12]; Carlos and Alberto elaborated on the solutions to load distribution on gear teeth [13]; Zhu et al delved into the characteristics of load sharing of planetary and encased differential herringbone train transmission systems from the Mechanism and Machine Theory 88 (2015) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] perspective of statics [14,15]; Fang et al studied the load-sharing characteristics of planetary and two-way power-split gear system [16,17]; Mo et al developed new structures of combined segmental double-helical annular gear used for planetary gear trains and star gear trains [18][19][20]. The GTF (Geared Turbofan Engine) aero-engine used double-helical planetary gear which is expected to be full-time without any additional maintenance outside normal maintenance periods [21].…”