scholarly journals Meshing Stiffness Parametric Vibration of Coaxial Contrarotating Encased Differential Gear Train

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Donglin Zhang ◽  
Rupeng Zhu ◽  
Miaomiao Li ◽  
Wuzhong Tan ◽  
Pingjun Li
Keyword(s):  
Planetary Gear ◽  
Peak Position ◽  
Gear Train ◽  
Parametric Vibration ◽  
Load Factor ◽  
Mechanical Transmission ◽  
Time Varying ◽  
Meshing Stiffness ◽  
Differential Gear ◽  
Combined Resonance

Planetary gears are widely used in mechanical transmission systems, but the vibration and noise affect their reliability and life. In this paper, the torsional dynamic model of an encased differential planetary gear with coaxial contrarotating outputs considering the time-varying meshing stiffness, damping, and phase difference of all gear pairs is established. By solving the equations of the derived system, three types of natural frequencies with different multiplicities of the system are obtained. The multiscale method is used to study the parametric vibration stability caused by the time-varying meshing stiffness, and the results are verified by numerical simulation. The dynamic characteristics of elastic meshing force are analyzed from time domain and frequency domain. The variation of the dynamic load factor of each gear pair with input speed and the relationship between its peak position and the natural frequency of the derived system are discussed. The results show that there is an unequal coupling phenomenon of meshing frequency between the meshing forces of different planetary sets. In the absence of external excitation, the meshing stiffness parameters not only excite the main resonance response of the system but also cause superharmonic resonance, subharmonic resonance, and combined resonance.

scholarly journals Mesh Phase Analysis of Encased Differential Gear Train for Coaxial Twin-Rotor Helicopter

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Donglin Zhang ◽  
Rupeng Zhu ◽  
Bibo Fu ◽  
Wuzhong Tan
Keyword(s):  
Phase Difference ◽  
Gear Tooth ◽  
Phase Relations ◽  
Gear Train ◽  
Time Varying ◽  
Gear Pair ◽  
Meshing Stiffness ◽  
Differential Gear ◽  
Starting Point ◽  
Twin Rotor

Dynamic excitation caused by time-varying meshing stiffness is one of the most important excitation forms in gear meshing process. The mesh phase relations between each gear pair are an important factor affecting the meshing stiffness. In this paper, the mesh phase relations between gear pairs in an encased differential gear train widely used in coaxial twin-rotor helicopters are discussed. Taking the meshing starting point where the gear tooth enters contact as the reference point, the mesh phase difference between adjacent gear pairs is analyzed and calculated, the system reference gear pair is selected, and the mesh phase difference of each gear pair relative to the system reference gear pair is obtained. The derivation process takes into account the modification of the teeth, the processing, and assembly of the duplicate gears, which makes the calculation method and conclusion more versatile. This work lays a foundation for considering the time-varying meshing stiffness in the study of system dynamics, load distribution, and fault diagnosis of compound planetary gears.

Time Varying Meshing Stiffness of Cracked Sun and Ring Gears of Planetary Gear Train

2015 ◽  
Vol 772 ◽  
pp. 164-168
Author(s):  
Arif Abdullah Muhammad ◽  
Guang Lei Liu
Keyword(s):  
Gear Tooth ◽  
Planetary Gear ◽  
Mesh Point ◽  
Gear Train ◽  
Time Varying ◽  
Planetary Gear Train ◽  
Meshing Stiffness ◽  
Face Width ◽  
The Face ◽  
Applied Forces

The time varying meshing stiffness of normal and cracked spur gears of planetary gear train is studied by applying the unit normal forces at mesh point on the face width along the line of action of the single gear tooth in FE based software Ansys Workbench 14.5. The tooth deflections due to the applied forces at one mesh point are noted and a deflection matrix is established which is solved using Matlab to get net deflection and finally the meshing stiffness of gear tooth at particular mesh point. The process is repeated for other mesh points of gear tooth by rotating it to get meshing stiffness for whole gear tooth.

Dynamic Simulation of 2K-H Differential Gear Train with Time-Varying Meshing Stiffness

2011 ◽  
Vol 314-316 ◽  
pp. 1603-1606
Author(s):  
Ying Chen Ma ◽  
Yan Wang ◽  
Ji Sheng Ma ◽  
Hai Ping Liu
Keyword(s):  
Life Prediction ◽  
Theoretical Data ◽  
Gear System ◽  
Gear Train ◽  
Time Varying ◽  
Meshing Stiffness ◽  
Torsion Vibration ◽  
Differential Gear ◽  
Gear Contact ◽  
Object Dynamic

Taking 2K-H differential gear train as study object, dynamic equation of torsion vibration was established with influence of time-varying meshing stiffness. The virtual-prototype with nonlinear meshing force was modeled using Virtual.Lab Motion software. Gear contact force was simulated, and it was verified by theoretical data. The reason of meshing vibration is analyzed. The results show that time-varying meshing stiffness is the main excitation of gear system, and gear system is vibratory although the input and output are stable, and the basic frequency is meshing frequency. This research lays foundation for strength checking, optimum design and fatigue life prediction.

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.

Analysis of power flow in a counter-rotating epicyclic gearing for electrical propulsion system

2011 ◽  
Vol 225 (12) ◽  
pp. 2973-2980
Author(s):  
W K Shi ◽  
L J Li ◽  
D T Qin ◽  
T C Lim
Keyword(s):  
Power Distribution ◽  
Power Flow ◽  
Planetary Gear ◽  
Unmanned Vehicles ◽  
Propulsion System ◽  
Gear Train ◽  
Planetary Gear Train ◽  
Differential Gear ◽  
Electrical Propulsion ◽  
Single Input

A novel compound epicyclic gearing that combines a planetary gear train with a differential gear train is designed for an electrical propulsion system of underwater unmanned vehicles. This epicyclic gearing can transform a single input into two counter-rotating outputs with equal torque amplitudes and speeds. Based on the analysis method of power flow in the differential gear train, the character of the power flow of the compound epicyclic gearing was determined. After comparing with the power distribution of input flow, the condition of this mechanism without power recirculation was investigated. Because the reactive torque of the motor stator is balanced by the torque on ring gear of planetary gear train, no net torque acts on the vessel being propelled.

scholarly journals Stress Assessment of Gear Teeth in Epicyclic Gear Train for Radial Sedimentation Tank

2020 ◽  
Vol 14 (3) ◽  
pp. 121-127
Author(s):  
Grzegorz Budzik ◽  
Tadeusz Markowski ◽  
Michał Batsch ◽  
Jadwiga Pisula ◽  
Jacek Pacana ◽  
...  
Keyword(s):  
Planetary Gear ◽  
Gear Train ◽  
Load Factor ◽  
The Finite Element Method ◽  
Gear Teeth ◽  
Gear Mesh ◽  
Sedimentation Tank ◽  
Epicyclic Gear ◽  
Comparison Of The Results ◽  
Root Stress

Abstract The paper presents the strength evaluation of planetary gear teeth designed for a radial sedimentation tank drive. A novel type of gear drive, composed of a closed epicyclic gear train and an open gear train with internal cycloidal gear mesh is proposed. Contact stress and root stress in the planetary gear train were determined by the finite element method and according to ISO 6336. The influence of the mesh load factor at planet gears on stress values was also established. A comparison of the results followed. It was observed that the mesh load factor on satellites depends mainly on the way the satellites and central wheels are mounted, the positioning accuracy in the carrier and the accuracy of teeth. Subsequently, a material was selected for the particular design of planetary gear and the assumed load. The analysis of the obtained results allowed assuming that in case of gears in class 7 and the rigid mounting of satellites and central wheels, gears should be made of steel for carburizing and hardening. In case of flexible satellites or flexible couplings in the central wheels and gears in class 4, gears can be made of nitriding steel.

scholarly journals Dynamic Characteristics of Encased Differential Gear Train with Journal Bearing

2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Jie Yang ◽  
Yanjiong Yue ◽  
Rupeng Zhu ◽  
Weifang Chen ◽  
Miaomiao Li
Keyword(s):  
Dynamic Model ◽  
Journal Bearing ◽  
Transmission Error ◽  
Gear Train ◽  
Meshing Stiffness ◽  
Differential Gear ◽  
Gearbox Vibration ◽  
Stiffness And Damping ◽  
Film Stiffness ◽  
Design And Manufacture

Taking the marine encased differential gear train as an example, the relationship between the journal bearing parameters and the meshing force of the transmission system is analyzed. In this paper, the dynamic model of the encased differential gear train with journal bearing is established considering the factors of time-varying meshing stiffness and comprehensive transmission error. In this dynamic model, four stiffnesses and four damping coefficients are applied to characterize the asymmetry and interaction of the oil film stiffness and damping of planet bearing. The system responses are calculated by the Fourier series numerical algorithm. The results show that the introduction of journal bearing in encased differential gear train can contribute to gearbox vibration reduction. Moreover, the planet bearing parameters (e.g., clearance-to-radius ratio and eccentricity ratio) of the differential stage affect the meshing forces of both the differential and encased stages. In addition, the influence of the planet bearing parameters of the encased stage on the meshing force of the encased stage is more obvious than that of the differential stage. This work may develop a theoretical analysis framework for the design and manufacture of marine transmission systems in the future.

Study on Dynamic Load Sharing Behavior of Two-Stage Planetary Gear Train Based on a Nonlinear Vibration Model

2011 ◽  
Vol 86 ◽  
pp. 611-614 ◽  
Author(s):  
Tong Jie Li ◽  
Ru Peng Zhu ◽  
He Yun Bao
Keyword(s):  
Planetary Gear ◽  
Load Sharing ◽  
Gear Train ◽  
Two Stage ◽  
Transmission Errors ◽  
Meshing Stiffness ◽  
Vibration Model ◽  
Planetary Gear System ◽  
Dynamic Load Sharing ◽  
Sharing Behavior

The nonlinear torsional vibration model of a two-stage planetary gear system is established taking errors of transmission, time varying meshing stiffness and multiple gear backlashes into account. The solution of the equations is determined by using ODE45. The influences of transmission errors on the load sharing behavior are assessed and some useful theoretical guidelines for the design of planetary gear systems are provided at last.

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