Modal analysis of modified planetary gear transmission based on real meshing stiffness

2015 ◽  
Author(s):  
Liu Lingtao ◽  
Ma Chao ◽  
Wang Shaohong
Keyword(s):  
Modal Analysis ◽  
Planetary Gear ◽  
Gear Transmission ◽  
Meshing Stiffness

Dynamical Analysis of Planetary Gear Transmission System Under Support Stiffness Effects

2020 ◽  
Vol 30 (06) ◽  
pp. 2050080
Author(s):  
Ling Xiang ◽  
Zeqi Deng ◽  
Aijun Hu
Keyword(s):  
Excitation Frequency ◽  
Global Bifurcation ◽  
Planetary Gear ◽  
Transmission System ◽  
Gear Transmission ◽  
Dynamic Responses ◽  
Dynamical Analysis ◽  
Largest Lyapunov Exponent ◽  
Meshing Stiffness ◽  
Gear Transmission System

The transverse-torsional nonlinear model of multistage gear transmission system which is comprised of a planetary gear set and two parallel gear stages is proposed with time-varying meshing stiffness, comprehensive gear errors and gear backlash. The nonlinear dynamic responses are analyzed by applying excitation frequency and support stiffness as the bifurcation parameters. The motions of the system are identified through global bifurcation diagram, largest Lyapunov exponent (LLE) and Poincaré map. The numerical results demonstrate that the support stiffness affects the system, especially on planetary gear set. The motions of the system with the changes of the support stiffness are diverse including some different multiperiodic motions. Also, the state of the system undergoes 2T-periodic motion, chaos, quasi-periodic behavior and multiperiodic motion. For the support stiffness or other nonlinear factors of the gear system, the suitable range of working frequencies could make the system stable. Correspondingly, parameters of the system should be designed properly and controlled for the better operation and enhancing the life of the system.

A Myoelectric Controlled Prosthetic Hand Modelling and its Transmission Mechanism Dynamic Load Based on a Two-Stage Planetary Gear Transmission

2013 ◽  
Vol 658 ◽  
pp. 298-304
Author(s):  
Ren Ping Shao ◽  
Jing Li ◽  
Xin Na Huang ◽  
Li Qun Chen
Keyword(s):  
Dynamic Load ◽  
Longitudinal Vibration ◽  
Planetary Gear ◽  
Transmission Efficiency ◽  
Gear Transmission ◽  
Transmission Mechanism ◽  
Prosthetic Hand ◽  
Analysis Model ◽  
Transmission Scheme ◽  
Meshing Stiffness

A new transmission scheme for the myoelectric prosthetic hand is proposed and establishes its 3D parametric model. In order to improve the transmission efficiency and reduce vibration、noise and shock in the situation of the smallest volume. Meanwhile considering the time-varying meshing stiffness of gear pair, lateral vibration, longitudinal vibration and the vibration along the meshing line direction of sun gear and planetary gear, the dynamic analysis model of dual output planetary gear transmission mechanism for the myoelectric prosthetic hand is established. By analyzing the dynamic model, the dynamic characteristics, dynamic response and dynamic load of system are obtained, which lays a foundation for dynamic design of the myoelectric prosthetic hand further.

Nonlinear Dynamics of a Multistage Gear Transmission System with Multi-Clearance

2018 ◽  
Vol 28 (03) ◽  
pp. 1850034 ◽  
Author(s):  
Ling Xiang ◽  
Yue Zhang ◽  
Nan Gao ◽  
Aijun Hu ◽  
Jingtang Xing
Keyword(s):  
Nonlinear Dynamics ◽  
Global Bifurcation ◽  
Planetary Gear ◽  
Transmission System ◽  
Gear Transmission ◽  
Dynamic Responses ◽  
Largest Lyapunov Exponent ◽  
Periodic Motions ◽  
Meshing Stiffness ◽  
Gear Transmission System

The nonlinear torsional model of a multistage gear transmission system which consists of a planetary gear and two parallel gear stages is established with time-varying meshing stiffness, comprehensive gear error and multi-clearance. The nonlinear dynamic responses are analyzed by applying the reference of backlash bifurcation parameters. The motions of the system on the change of backlash are identified through global bifurcation diagram, largest Lyapunov exponent (LLE), FFT spectra, Poincaré maps, the phase diagrams and time series. The numerical results demonstrate that the system exhibits rich features of nonlinear dynamics such as the periodic motion, nonperiodic states and chaotic states. It is found that the sun-planet backlash has more complex effect on the system than the ring-planet backlash. The motions of the system with backlash of parallel gear are diverse including some different multi-periodic motions. Furthermore, the state of the system can change from chaos into quasi-periodic behavior, which means that the dynamic behavior of the system is composed of more stable components with the increase of the backlash. Correspondingly, the parameters of the system should be designed properly and controlled timely for better operation and enhancing the life of the system.

scholarly journals Nonlinear dynamics modelling of multistage micro-planetary gear transmission

2018 ◽  
Vol 153 ◽  
pp. 03005 ◽  
Author(s):  
Jianying Li ◽  
Zhiyong Xu ◽  
Qingchun Hu ◽  
Changfu Zong ◽  
Tianjun Zhu
Keyword(s):  
Dynamic Modelling ◽  
Elastohydrodynamic Lubrication ◽  
Planetary Gear ◽  
Transmission Error ◽  
Relative Displacement ◽  
Gear Transmission ◽  
Meshing Stiffness ◽  
Coupling Stiffness ◽  
Transmission Structure ◽  
Three Stages

The transmission structure of a 2K-H multistage micro-planetary gear transmission reducer is described in detail, and three assumptions are supposed in dynamic modelling. On basis of these assumptions, a three stages 2K-H micro-planetary gear transmission dynamic model is established, in which the relative displacement each meshing gear pairs can be obtained after including the comprehensive transmission error. According to gear kinematics, the friction arms between the sun gear, the ring gear and the nth planet are also obtained, and the friction coefficient in the mixed elastohydrodynamic lubrication is considered, the transmission system motion differential equations are obtained, including above factors and the time-varying meshing stiffness, damping and backlash, inter-stage coupling stiffness, it can be provided an theoretical foundation for further analysing the parameter sensitivity, dynamic stability and designing.

Modelling and modal analysis of a hoist equipped with two-stage planetary gear transmission system

2016 ◽  
Vol 231 (4) ◽  
pp. 739-749 ◽  
Author(s):  
Wei Yang ◽  
Xiaolin Tang
Keyword(s):  
Modal Analysis ◽  
Natural Frequencies ◽  
Planetary Gear ◽  
Transmission System ◽  
Gear Transmission ◽  
Gear Train ◽  
Contact Method ◽  
Two Stage ◽  
Gear Transmission System ◽  
Viscoelastic Contact

The connection between a gear pair is commonly treated as constant stiffness in the literature of planetary gear transmission dynamics, leading to inaccurate results. Based on the theory of viscoelastic contact, according to low speed or stationary gear pairs have the characteristics of small relative sliding velocity, viscoelastic contact method is proposed to solve this problem. A hoist equipped with two-stage planetary gear reducer is used as research object to investigate the dynamic properties. The natural frequencies and corresponding vibration modes of this planetary gear transmission system are presented. Accordingly, the natural frequencies are recognized using operational modal analysis under ambient excitation, and the experimental studies are in close agreement with theoretical expectation. In addition, the dynamic behaviours of this planetary gear train are investigated.

scholarly journals Dynamic characteristics analysis of planetary gear system with internal and external excitation under turbulent wind load

2021 ◽  
Vol 104 (3) ◽  
pp. 003685042110356
Author(s):  
Hexu Yang ◽  
Xiaopeng Li ◽  
Jinchi Xu ◽  
Zemin Yang ◽  
Renzhen Chen
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Nonlinear Dynamic ◽  
Planetary Gear ◽  
Wind Load ◽  
Transmission System ◽  
Gear Transmission ◽  
Stiffness Ratio ◽  
Gear Transmission System ◽  
Planetary Gear System

According to the working characteristics of a 1.5 MW wind turbine planetary gear system under complex and random wind load, a two-parameter Weibull distribution model is used to describe the distribution of random wind speed, and the time-varying load caused by random wind speed is obtained. The nonlinear dynamic model of planetary gear transmission system is established by using the lumped parameter method, and the relative relations among various components are derived by using Lagrange method. Then, the relative relationship between the components is solved by Runge Kutta method. Considering the influence of random load and stiffness ratio on the planetary gear transmission system, the nonlinear dynamic response of cyclic load and random wind load on the transmission system is analyzed. The analysis results show that the variation of the stiffness ratio makes the planetary gear have abundant nonlinear dynamics behavior and the planetary gear can get rid of chaos and enter into stable periodic motion by changing the stiffness ratio properly on the premise of ensuring transmission efficiency. For the variable pitch wind turbine, the random change of external load increases the instability of the system.

Influence of the backlash generated by tooth accumulated wear on dynamic behavior of compound planetary gear set

2016 ◽  
Vol 231 (11) ◽  
pp. 2025-2041 ◽  
Author(s):  
Shijing Wu ◽  
Haibo Zhang ◽  
Xiaosun Wang ◽  
Zeming Peng ◽  
Kangkang Yang ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Planetary Gear ◽  
Tooth Wear ◽  
Transmission Error ◽  
Gear Transmission ◽  
Tooth Surface ◽  
Contact Ratio ◽  
The Impact

Backlash is a key internal excitation on the dynamic response of planetary gear transmission. After the gear transmission running for a long time under load torque, due to tooth wear accumulation, the backlash between the tooth surface of two mating gears increases, which results in a larger and irregular backlash. However, the increasing backlash generated by tooth accumulated wear is generally neglected in lots of dynamics analysis for epicyclic gear trains. In order to investigate the impact of backlash generated by tooth accumulated wear on dynamic behavior of compound planetary gear set, in this work, first a static tooth surface wear prediction model is incorporated with a dynamic iteration methodology to get the increasing backlash generated by tooth accumulated wear for one pair of mating teeth under the condition that contact ratio equals to one. Then in order to introduce the tooth accumulated wear into dynamic model of compound planetary gear set, the backlash excitation generated by tooth accumulated wear for each meshing pair in compound planetary gear set is given under the condition that contact ratio equals to one and does not equal to one. Last, in order to investigate the impact of the increasing backlash generated by tooth accumulated wear on dynamic response of compound planetary gear set, a nonlinear lumped-parameter dynamic model of compound planetary gear set is employed to describe the dynamic relationships of gear transmission under the internal excitations generated by worn profile, meshing stiffness, transmission error, and backlash. The results indicate that the introduction of the increasing backlash generated by tooth accumulated wear makes a significant influence on the bifurcation and chaotic characteristics, dynamic response in time domain, and load sharing behavior of compound planetary gear set.

Dynamic Characteristics of Double Helical Planetary Gear Train With Tooth Friction

2015 ◽  
Author(s):  
Fengxia Lu ◽  
Rupeng Zhu ◽  
Haofei Wang ◽  
Heyun Bao ◽  
Miaomiao Li
Keyword(s):  
Degrees Of Freedom ◽  
Sliding Friction ◽  
Planetary Gear ◽  
Gear Train ◽  
Variable Step Size ◽  
Step Size ◽  
Planetary Gear Train ◽  
Gear Mesh ◽  
Meshing Stiffness ◽  
Nonlinear Dynamics Model

A new nonlinear dynamics model of the double helical planetary gear train with 44 degrees of freedom is developed, and the coupling effects of the sliding friction, time-varying meshing stiffness, gear backlashes, axial stagger as well as gear mesh errors, are taken into consideration. The solution of the differential governing equation of motion is solved by variable step-size Runge-Kutta numerical integration method. The influence of tooth friction on the periodic vibration and nonlinear vibration are investigated. The results show that tooth friction makes the system motion become stable by the effects of the periodic attractor under the specific meshing frequency and leads to the frequency delay for the bifurcation behavior and jump phenomenon in the system.

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