Lumped Parameter Model of Planetary Gear Systems

1978 ◽  
Vol 192 (1) ◽  
pp. 251-258 ◽  
Author(s):  
J. W. Polder
Keyword(s):  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Lumped Parameter Model ◽  
Damping Coefficients ◽  
Planetary Gear Trains ◽  
Lumped Parameter ◽  
Vibration Model ◽  
Close Relationship ◽  
Angular Velocities ◽  
Gear Trains

A model system is described by parameters for shafts, planetary gear trains and nodes. Moments of inertia, spring stiffnesses and damping coefficients are assigned to the shafts; gear ratios and efficiencies are assigned to planetary gear trains. The equivalence of angular velocities and torques is demonstrated for shafts (vibration model), as well as for planetary gear trains and nodes (configuration of the system). This brings about a new view on the concept of degrees of freedom. The close relationship between gear ratios and torque ratios yields identical functions for these ratios when applied to the input and output shafts of a system. The full use of this relationship requires strict conventions of signs and an extension of the interpretation of values. The introduction of a new concept, named responsivity, expresses the relationships between torques and between powers of arbitrary shafts. With suitable equations, it becomes possible to investigate torque and power distributions exhaustively.

Random Vibration Analysis of Planetary Gear Trains

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Jianming Yang ◽  
Ping Yang
Keyword(s):  
Sample Path ◽  
Planetary Gear ◽  
Gear Train ◽  
Lumped Parameter Model ◽  
State Variables ◽  
Random Loads ◽  
Planetary Gear Trains ◽  
Lumped Parameter ◽  
Gear Trains ◽  
The Mean

This article investigates the vibration response of a planetary gear train under excitations of both deterministic and random loads. A lumped parameter model has been used in this investigation and the random excitations are represented by white noise. One version of the stochastic Newmark algorithms is employed to solve for both sample path response and the statistics of the response. The mean and the variance for all state variables are obtained through the same algorithm. The effects of three different levels of noise on the statistics are compared against each other.

Dynamic Modeling of the Torsional Vibration of the Slewing Mechanism of a Hydraulic Excavator

2012 ◽  
Vol 253-255 ◽  
pp. 2102-2106 ◽  
Author(s):  
Xu Juan Yang ◽  
Zong Hua Wu ◽  
Zhao Jun Li ◽  
Gan Wei Cai
Keyword(s):  
Torsional Vibration ◽  
Natural Frequencies ◽  
Planetary Gear ◽  
Moment Of Inertia ◽  
Hydraulic Excavator ◽  
Planetary Gear Trains ◽  
Vibration Model ◽  
Gear Trains ◽  
The Moment ◽  
Relationship Of

A torsional vibration model of the slewing mechanism of a hydraulic excavator is developed to predict its free vibration characteristics with consideration of many fundamental factors, such as the mesh stiffness of gear pairs, the coupling relationship of a two stage planetary gear trains and the variety of moment of inertia of the input end caused by the motion of work equipment. The natural frequencies are solved using the corresponding eigenvalue problem. Taking the moment of inertia of the input end for example to illustrate the relationship between the natural frequencies of the slewing mechanism and its parameters, based on the simulation results, just the first order frequency varies significantly with the moment of inertia of the input end of the slewing mechanism.

Conceptual Design of Gear Differentials for Automotive Vehicles

1994 ◽  
Vol 116 (2) ◽  
pp. 565-570 ◽  
Author(s):  
Hong-Sen Yan ◽  
Long-Chang Hsieh
Keyword(s):  
Conceptual Design ◽  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Gear Train ◽  
Design Constraints ◽  
Two Degrees Of Freedom ◽  
Design Concepts ◽  
Planetary Gear Trains ◽  
Gear Trains ◽  
Gear Differential

An automotive gear differential is a joint-fractionated planetary gear train with two degrees-of-freedom. We summarize the characteristics of planetary gear trains and the design constraints of noncoupled automotive gear differentials to synthesize their corresponding kinematic graphs. Based on these graphs and the proposed respecializing process, we generate the atlas of design concepts for automotive gear differentials with any types of gear pairs. As a result, there are 4, 25, and 156 design concepts for five-, six-, and seven-bar automotive gear differentials, respectively.

scholarly journals Work of the planetary gear trains as differentials and their capabilities

2019 ◽  
Vol 287 ◽  
pp. 04001
Author(s):  
Kiril Arnaudov ◽  
Stefan Petrov ◽  
Emiliyan Hristov
Keyword(s):  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Gear Ratio ◽  
Gear Train ◽  
Motor Drive ◽  
Planetary Gear Train ◽  
Maximum Security ◽  
Single Carrier ◽  
Planetary Gear Trains ◽  
Gear Trains

Planetary gear trains can work differently, namely, with F=1 degree of freedom, i.e. as reducers or multipliers, and also with F=2 degrees of freedom, i.e. as differentials. Moreover, with a two-motor drive they work as a summation planetary gear train and with a one-motor drive, they work as a division planetary gear train. The most popular application of planetary gear trains is as a differential which is bevel and is produced globally in millions of pieces. Some of the cylindrical planetary gear trains can also be used as differentials. Although less often, they are used in heavy wheeled and chain vehicles such as trailer trucks, tractors and tanks. They are also very suitable for lifting machines with a two-motor drive which provides maximum security for the most responsible cranes, such as the metallurgical ones. Initially the paper presents some simple, i.e. single-carrier cylindrical planetary gear trains, both with external and internal meshing, driven by 2 motors. Their kinematic capabilities and velocity, respectively, are considered to realize the necessary gear ratio. Finally, the case of a compound two-carrier planetary gear train is considered, which is composed of 2 simple planetary gear trains. This shows that not only the simple planetary gear trains, i.e. the single-carrier ones, can work as differentials.

A GEAR-SHIFTING MECHANISM WITH A ROTARY CONFIGURATION FOR APPLICATIONS IN A 16-SPEED BICYCLE TRANSMISSION HUB

2016 ◽  
Vol 40 (4) ◽  
pp. 597-606
Author(s):  
Yi-Chang Wu ◽  
Li-An Chen
Keyword(s):  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Systematic Design ◽  
Embodiment Design ◽  
Planetary Gear Trains ◽  
Epicyclic Gear ◽  
Gear Mechanism ◽  
Gear Trains ◽  
To Come ◽  
Gear Differential

A multi-speed bicycle transmission hub includes a geared speed-changing mechanism for providing different speed ratios and a gear-shifting mechanism for controlling the gear stage. This paper focuses on the embodiment design of a mechanical gear-shifting mechanism with a rotary configuration used in a 16-speed transmission hub for bicycles. A 16-link, five-degrees of freedom (DOF) split-power epicyclic gear mechanism, which consists of a gear differential and four sets of parallel-connected basic planetary gear trains, is introduced. Based on the clutching sequence table, a systematic design process is developed to come up with the embodiment design of the gear-shifting mechanism. A feasible and compact 16-speed rear transmission hub for bicycles is presented.

Automatic Analysis of Kinematic Structure of Planetary Gear Trains

1993 ◽  
Vol 115 (3) ◽  
pp. 631-638 ◽  
Author(s):  
Cheng-Ho Hsu ◽  
Kin-Tak Lam
Keyword(s):  
Computer Program ◽  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Automatic Analysis ◽  
Kinematic Structure ◽  
Identification Number ◽  
Interactive Computer Program ◽  
Planetary Gear Trains ◽  
Gear Trains

This paper presents a systematic algorithm for the automatic analysis of the kinematic structure of planetary gear trains with any number of degrees of freedom. The canonical displacement graphs and rotation graphs are introduced to represent the kinematic structure of planetary gear trains. Next, a single identification number method is presented to identify the displacement isomorphism of planetary gear trains. Then, nonfractionated multi-DOF planetary gear trains can be identified from their rotation graphs. Finally, an interactive computer program is developed for the automatic analysis of the kinematic structure of planetary gear trains. The result of this work is beneficial to the development of the new planetary gear trains.

Design of Multiple Operating Degrees-of-Freedom Planetary Gear Trains With Variable Structure

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Zeng-Xiong Peng ◽  
Ji-Bin Hu ◽  
Tian-Li Xie ◽  
Chun-Wang Liu
Keyword(s):  
Power Flow ◽  
Degrees Of Freedom ◽  
Flow Analysis ◽  
Graph Model ◽  
Planetary Gear ◽  
Variable Structure ◽  
Planetary Gear Trains ◽  
Planetary Gear Sets ◽  
Gear Trains ◽  
Synthesis Methodology

To obtain multiple speed ratios, a synthesis methodology of planetary gear trains (PGTs) with multiple operating degrees-of-freedom (DOFs) is proposed based on the variable structure method. Variable structure of PGT is accomplished by changing the fixed interconnection edge. First, PGTs with two operating DOFs are synthesized with a deduction method based on the relationship between the number of planetary gear sets (PGSs) and number of fixed interconnection edges. Next, connection characteristics of fixed interconnection edges are defined as frequency of utilization to construct original speed ratios of the two operating DOFs schemes. The connection characteristics are then obtained based on the power flow analysis. PGT graph model with connection characteristic is built to provide guidance in the design of varying structure. Finally, multispeed PGTs with multiple operating DOFs are synthesized based on the graph model and lever analogy. A design example for three-PGS PGTs is considered to highlight capabilities of the variable structure method.

Self-Adaptive Underactuated Hybrid Rolling/Walking Locomotion

2012 ◽  
Author(s):  
Carl A. Nelson
Keyword(s):  
Degrees Of Freedom ◽  
Multiple Scales ◽  
Planetary Gear ◽  
Legged Locomotion ◽  
Robotic Locomotion ◽  
Uneven Terrain ◽  
Planetary Gear Trains ◽  
Obstacle Clearance ◽  
Gear Trains ◽  
And Control

In planetary exploration and other similar robotic applications, it is possible to encounter obstacles on multiple scales, making it difficult to design wheeled locomotion that works well for all terrain types. Legged locomotion tends to be less efficient and slower, but allows better obstacle clearance. This paper describes a novel method of achieving robotic locomotion over uneven terrain using a passive underactuation technique. Using planetary gear trains with one input degree of freedom and two output degrees of freedom, the natural obstacle-based locking of select outputs can cause the transition of power through the alternate outputs. By designing the primary outputs as wheels and the secondary outputs as legs with more ground clearance, a naturally adaptive hybrid gait incorporating both rolling and walking can be generated without the need for sophisticated sensing and control. Derivation and simulation validation are presented.

Dynamics Analysis of Planetary Gear Trains in a Wind Turbine Under Mean Wind Speed

2017 ◽  
Author(s):  
Jianming Yang ◽  
Ping Yang
Keyword(s):  
Wind Speed ◽  
Planetary Gear ◽  
Vibration Response ◽  
Lumped Parameter Model ◽  
Dynamic Force ◽  
Gear Mesh ◽  
Planetary Gear Trains ◽  
Mean Wind Speed ◽  
Gear Trains ◽  
Aerodynamic Torque

Targeting at planetary gear trains (PGTs) used in wind turbines, this paper investigates their vibration and dynamics under the aerodynamic torque of mean wind speed. Wind shear and tower shadow effects are considered in modeling the torque. A lumped parameter model is then developed to calculate the vibration and dynamics response of the PGT to the aerodynamic torque. In this model, the gear teeth and bearings are modeled as springs and the rotation of the carrier and the planet gears as well as the translation of the sun gear are taken into account. The time varying effect of the stiffness of gear mesh is incorporated into the model. Newmark algorithm is used to solve the vibration model established. In the last, the vibration response and dynamic meshing forces of the PGT are simulated and analyzed for rotors with 2 blades and 3 blades. The simulation result demonstrates that the aerodynamic torque is not a constant even under a constant wind speed. Instead, it changes with a frequency which equals the fundamental rotor frequency multiplied by the number of blades. The torque fluctuation causes corresponding vibration response and dynamic force fluctuation in the PGT.

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