Modeling and Dynamic Characteristics of Planetary Gear Transmission in Non-inertial System of Aerospace Environment

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Jing Wei ◽  
Aiqiang Zhang ◽  
Lei Shi ◽  
Datong Qin ◽  
Teik C. Lim
Keyword(s):  
Dynamic Behavior ◽  
Dynamic Characteristics ◽  
Planetary Gear ◽  
Gear Transmission ◽  
Dynamic Responses ◽  
Inertial System ◽  
Dominant Factor ◽  
Central Component ◽  
Traditional Research ◽  
Planet Gear

Abstract The traditional research on the dynamics of planetary gear transmission (PGT) is based on the assumption that the support is on the ground. However, the PGT inside the aircraft is spatially moved along with the airframe, which is not only subject to gravity, but also to additional inertia forces. These loads should affect the dynamic characteristics of the PGT. The PGT itself is a non-inertial system (NIS) and is called the internal non-inertial system (INIS). By contrast, an airframe in the aerospace environment is named an external non-inertial system (ENIS). In order to investigate the dynamic behavior of the PGT in a compound NIS, the kinematic equations of various components in arbitrary spatial motion state of the airframe are deduced. Subsequently, the coupled dynamics model of PGT in NIS is improved. The dynamic responses of PGT in different non-inertial conditions are compared based on the hovering motion of the airframe. The results indicate that INIS is the main factor affecting the trajectory of planet gear, while ENIS is the force source changing the trajectory of the central component. The aircraft’s hovering motion makes the gravity effect become a relatively time-varying excitation, but the dominant factor is still the additional inertial forces. The non-inertial effect during aerospace operation can significantly affect the bearing force, vibration and load sharing performance. It will lead to serious errors if the traditional research method is still used to obtain the dynamic behavior of PGT in the aerospace environment.

Modeling and Dynamic Characteristics of Planetary Gear Transmission in Non-Inertial System of Aerospace Environment

2019 ◽  
Author(s):  
Jing Wei ◽  
Lei Shi ◽  
Aiqiang Zhang ◽  
Datong Qin
Keyword(s):  
Dynamic Behavior ◽  
Dynamic Characteristics ◽  
Planetary Gear ◽  
Transmission System ◽  
Gear Transmission ◽  
Inertial System ◽  
Inertia Force ◽  
Central Component ◽  
Spatial Motion ◽  
Gear Transmission System

Abstract The traditional research on the dynamics of planetary gear transmission system is based on the assumption that the support is on the ground. However, the planetary gear transmission system inside the aircraft is spatially moved along with the airframe, which is not only subject to gravity, but also to convected inertia force and Coriolis inertia force, as well as gyroscopic moment. These loads affect the dynamic characteristics of the planetary gear transmission system. In order to investigate the dynamic behavior of planetary gear transmission system in non-inertial system of aerospace environment, the kinematic equations of the central component and planetary gear in arbitrary spatial motion state of the airframe are deduced with the influence of internal non-inertial system and external non-inertial system. Subsequently, the coupling dynamic model of planetary gear transmission system is established, which is in non-inertial system of aerospace environment. The motion variation law of planetary gear transmission system in the non-inertial system and the dynamic behavior of each component in different non-inertial conditions are researched based on the hovering motion of the airframe. The results indicate that the radial equilibrium position of the planetary gear has great offset due to the influence of non-inertial system inside the planetary gear train when the airframe has no spatial motion. Moreover, the gravity on each component will generate radial force, which and additional inertial force will vary with the external non-inertia conditions when the airframe is in the state of spatial motion. In addition, different non-inertial conditions have significant influence on the motion trajectory, bearing force and acceleration of each component, and have different influence rules on the central component and planetary gear.

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.

Effect of Track Geometric Irregularity on Dynamic Characteristics of Gear Transmission in a Locomotive

2017 ◽  
Author(s):  
Tao Zhang ◽  
Zaigang Chen ◽  
Jie Zhang ◽  
Shunqi Sui ◽  
Cheng Pan
Keyword(s):  
Dynamic Characteristics ◽  
Life Prediction ◽  
Dynamic Performance ◽  
Gear Transmission ◽  
Fatigue Life Prediction ◽  
Dynamic Responses ◽  
Mean Square ◽  
Track Irregularity ◽  
Working Performance ◽  
Statistical Indicators

Gear transmission is a key component in locomotive where it delivers the traction or braking forces between the motor and the wheelset. Its working performance has a direct effect on the operating reliability and safety. Therefore, investigation on the dynamic characteristics of the gear transmission in locomotives is very meaningful. In this study, a gear transmission-locomotive-track spatial coupled dynamic model is established based on the classical locomotive-track coupled dynamics and the gear dynamics theory. Based on this model, the dynamic responses of the gear transmission can be analysed under excitations from different track geometrical irregularity, and the dynamic performance of the gear transmission can be obtained. This paper also studies the effect law of the track irregularity on the vibration of the gear transmission by using statistical indicators RMS (Root Mean Square) and PtP (Peak-to-Peak). The results indicate that the track geometrical irregularity has an obvious impact to the dynamic performance of gear transmission. The dynamic response of the gear transmission will increase violently when the locomotive runs on the track in a worse condition. The results are expected to be capable of providing some references for fatigue life prediction and reliability analysis of the gear transmissions in locomotive.

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.

scholarly journals Dynamic Characteristics and Load Sharing of Herringbone Wind Power Gearbox

2018 ◽  
Vol 2018 ◽  
pp. 1-24 ◽  
Author(s):  
Shuai Mo ◽  
Ting Zhang ◽  
Guoguang Jin ◽  
Zhanyong Feng ◽  
Jiabei Gong ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Planetary Gear ◽  
Load Sharing ◽  
Transmission System ◽  
Gear Transmission ◽  
Torsional Stiffness ◽  
Gear Transmission System ◽  
Herringbone Gear ◽  
Stagger Angle ◽  
The Impact

In this study, the dynamic model for the herringbone planetary gear transmission system is established by the lumped parameter method based on the system dynamics and the Lagrange equation, and the impact of the support stiffness and the torsional stiffness on dynamic characteristics is studied. The research results have a guiding significance for the design of the herringbone gear transmission system. In this model, the herringbone gear is treated as a special gear coupled by 2 opposite helical gears, where the stagger angle, comprehensive meshing error, support stiffness, support damping, and load inertia are considered in the analysis of dynamics. Moreover, the dynamic characteristic of the carrier is considered as well. By calculating the meshing force curve of the transmission system, the impact of the stagger angle, supporting stiffness, and the torsional stiffness on meshing force and load sharing coefficient is analyzed. The results show that the stagger angle has an obvious impact on load sharing coefficient while it has little impact on maximum meshing force. And the support stiffness has a more obvious impact on the dynamic characteristics of the system. The recommendary support stiffness of the system is that all of the support stiffness of the sun gear, planetary gear, ring gear, and carrier is 107 N/m. The torsional stiffness has little impact on the dynamic characteristics of transmission system, except the torsional stiffness of planetary gear, and carrier has an obvious impact on load sharing coefficient. The commercial software ADAMS carried out dynamics analysis of the transmission system to verify the necessity validity of the theoretical analysis.

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.

Effects of Gear Manufacturing Error on the Dynamic Characteristics of Planetary Gear Transmission System of Wind Turbine

2011 ◽  
Vol 86 ◽  
pp. 518-522 ◽  
Author(s):  
Hui Tao Chen ◽  
Xiao Ling Wu ◽  
Da Tong Qin ◽  
Jun Yang ◽  
Zhi Gang Zhou
Keyword(s):  
Wind Turbine ◽  
Dynamic Characteristics ◽  
Planetary Gear ◽  
Transmission System ◽  
Gear Transmission ◽  
Statistical Characteristics ◽  
Direct Drive ◽  
Manufacturing Error ◽  
Gear Transmission System ◽  
Gear Manufacturing

The effects of gear manufacturing error on the dynamic characteristics of planetary gear transmission system of wind turbine are studied in this paper. Firstly, the static transmission error combined with manufacturing error of the gear is deduced. Then, the nonlinear dynamic model of planetary gear transmission system of wind turbine is set up with the consideration of time-varying mesh stiffness, backlash and manufacturing error. Finally, the statistical characteristics of Vibration displacement response process of each component of planetary gear transmission system are obtained by simulation analysis of the planetary gear system of 1.5MW Semi-direct drive wind turbine with the consideration of the torque fluctuation caused by wind speed. The research results lay a foundation for reliability design and optimizing of gear transmission system of wind turbine.

Elastohydrodynamic Lubrication Design of Planetary Gear Transmission

2011 ◽  
Vol 228-229 ◽  
pp. 681-685
Author(s):  
Pei De Bao ◽  
Jun Xie ◽  
Xiao Qin Yin ◽  
Qi Zhi Yang ◽  
Lu Zhong Ma
Keyword(s):  
Film Thickness ◽  
Hydrodynamic Lubrication ◽  
Elastohydrodynamic Lubrication ◽  
Planetary Gear ◽  
Gear Transmission ◽  
The Sun ◽  
Oil Film ◽  
Lubrication Film ◽  
Planet Gear ◽  
The Many

Based on elastic hydrodynamic lubrication (EHL) theory, an EHL model of the meshing between the sun gear and planet gear in planetary gear transmission was established. The EHL oil film thicknesses at meshing areas and those distributions for two operation cases were calculated: one case with the sun gear as the driving gear and another case with the ring gear as the driving gear. The Lubrication with second case was worse. Through the many comparing calculations the lubrication film thickness can be significantly increased by right parameter design. Reasonable raise of lubricant viscosity can get better gear lubrication. Increased gear pressure angle can greatly increase the oil film thickness. The increase of oil film thickness can improve the lubrication of gears and prevent wearing and reduce the production cost of gears, which have great practical value.

scholarly journals Fault Diagnosis of Planet Gear Using Continuous Vibration Separation and Minimum Entropy Deconvolution

2020 ◽  
Vol 10 (22) ◽  
pp. 8062
Author(s):  
Jian Shen ◽  
Lun Zhang ◽  
Niaoqing Hu
Keyword(s):  
Fault Diagnosis ◽  
Planetary Gear ◽  
Dynamic Responses ◽  
Minimum Entropy ◽  
Modulation Effect ◽  
Dynamic Component ◽  
Planetary Gearbox ◽  
Gear Fault ◽  
Vibration Responses ◽  
Planet Gear

Planet gear is the most unique dynamic component in planetary gearbox. It rotates around sun gear while rotating around its own central axis, causing modulation effect in monitoring signal. Planetary gear is usually connected to heavy external loads and other transmissions, fault feature of planet gear may be overwhelmed by noises and other signals. Focused on planet gear inside planetary gearbox, a method for fault diagnosis is proposed in this paper based on continuous vibration separation (CVS) and minimum entropy deconvolution (MED). In this method, CVS is designed to separate dynamic responses of planet gear from overall vibration responses of planetary gearbox by overcoming the modulation effect and depressing noises. MED is used for enhancement detection of fault-related impulses. Simulations and experiments are conducted to collect signals for analysis. The proposed method is also compared with vibration separation method (VS). Both simulation and experiment analysis indicate that the proposed planet gear fault diagnosis method is effective. Comparative study indicates that CVS-MED method improves VS by keeping signal periodicity while overcoming modulation effect and depressing noises.

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