Effect of Internal Gear Flexibility on the Quasi-Static Behavior of a Planetary Gear Set

2000 ◽  
Vol 123 (3) ◽  
pp. 408-415 ◽  
Author(s):  
Ahmet Kahraman ◽  
Sandeep Vijayakar
Keyword(s):  
Finite Elements ◽  
Contact Mechanics ◽  
State Of The Art ◽  
Automatic Transmission ◽  
Planetary Gear ◽  
Static Behavior ◽  
Nonlinear Contact ◽  
Bending Stresses ◽  
Deformable Bodies ◽  
Internal Gear

Effect of flexibility of an internal gear on the quasi-static behavior of a planetary gear set is investigated. A state-of-the-art finite elements/semi-analytical nonlinear contact mechanics formulation is employed to model a typical automotive automatic transmission planetary unit. The model considers each gear as deformable bodies and meshes them to predict loads, stresses and deformations of the gears. Actual support and spline conditions are included in the model. The rim thickness of the internal gear is varied relative to the tooth height and gear deflections and bending stresses are quantified as a function of rim thickness. Influence of rim thickness on the load sharing amongst the planets is also investigated with and without floating sun gear condition. The results are discussed in detail and guidelines regarding the design of a planetary internal gear are presented.

Effect of Internal Gear Flexibility on the Quasi-Static Behavior of a Planetary Gear Set

2000 ◽  
Author(s):  
Ahmet Kahraman ◽  
Sandeep Vijayakar
Keyword(s):  
Contact Mechanics ◽  
State Of The Art ◽  
Automatic Transmission ◽  
Planetary Gear ◽  
Load Sharing ◽  
Static Behavior ◽  
Nonlinear Contact ◽  
Bending Stresses ◽  
Deformable Bodies ◽  
Internal Gear

Abstract Effect of flexibility of an internal gear on the quasi-static behavior of a planetary gear set is investigated. A state-of-the-art FEM/semi-analytical nonlinear contact mechanics formulation is employed to model a typical automotive automatic transmission planetary unit. The model considers each gear as deformable bodies, and meshes them to predict loads, stresses and deformations of the gears. Actual support and spline conditions are included in the model. The rim thickness of the internal gear is varied relative to the tooth height and gear deflections and bending stresses are quantified as a function of rim thickness. Influence of rim thickness on the load sharing amongst the planets is also investigated with and without floating sun gear condition. The results are discussed in detail and guidelines regarding the design of a planetary internal gear are presented.

Effect of Rim Thickness on Tooth Root Stress and Mesh Stiffness of Internal Gears

2014 ◽  
Author(s):  
F. Karpat ◽  
B. Engin ◽  
O. Dogan ◽  
C. Yuce ◽  
T. G. Yilmaz
Keyword(s):  
Weight Ratio ◽  
Planetary Gear ◽  
Mesh Stiffness ◽  
Gear Mesh ◽  
Aerospace Applications ◽  
Bending Stresses ◽  
Gear Mechanism ◽  
Internal Gear ◽  
Gear Mesh Stiffness ◽  
Root Stress

In recent years, internal gears are used commonly in a number of automotive and aerospace applications especially in planetary gear drives. Planetary gears have many advantages such as compactness, large torque-to-weight ratio, large transmission ratios, reduced noise and vibrations. Although internal gears have many advantages, there are not enough studies on it. Designing an internal gear mechanism includes two important parameters. The gear mesh stiffness which is the main excitation source of the system. In this paper, 2D gear models are developed in order to compute gear mesh stiffness for various rim thicknesses and different rim shapes of the internal gear design. Effects of root stress with varying rim thickness and some tooth parameters are investigated by using 2D gear models. The stress calculated according to ISO 6336 and the stresses calculated against FEM are compared. These results are well-matched. It is observed that when the rim thicknesses are increased, both the maximum bending stresses and gear mesh stiffness are decreased considerably.

Dynamic Analysis of Planetary Gear Reducer

2018 ◽  
Vol 880 ◽  
pp. 87-92
Author(s):  
Daniela Vintilă ◽  
Laura Diana Grigorie ◽  
Alina Elena Romanescu
Keyword(s):  
Finite Elements ◽  
Differential Equations ◽  
Dynamic Analysis ◽  
Frequency Response ◽  
Planetary Gear ◽  
Resonance Phenomenon ◽  
Superposition Method ◽  
Planetary Gears ◽  
Tower Crane ◽  
Systems Of Differential Equations

This paper presents dynamic analysis of a three stage planetary gear reducer for operate a tower crane. Ordinary and planetary gears have been designed respecting the coaxial, neighboring and mounting conditions. Harmonic analysis has been processed to identify frequency response for displacements, strains and deformations. The aim of the study was to determine critical frequencies to avoid mechanical resonance phenomenon. The obtained results are based on the superposition method for solving the systems of differential equations resulting from the analysis with finite elements.

scholarly journals Introduction of a redundant actuator using planetary gear trains for human centred robotics

2020 ◽  
Vol 317 ◽  
pp. 01003
Author(s):  
Stein Crispel ◽  
Pablo López-García ◽  
Tom Verstraten ◽  
Elias Saerens ◽  
Dirk Lefeber
Keyword(s):  
State Of The Art ◽  
Planetary Gear ◽  
Electric Cars ◽  
Planetary Gear Trains ◽  
Continuously Variable Transmissions ◽  
Redundant Actuators ◽  
Gear Trains ◽  
And Performance ◽  
Human Limb ◽  
Multiple Transmission

Matching motor efficiency and performance with the load demands can significantly improve the overall efficiency of a driveline. Inspired by the automotive sector -with the high interest of hybrid and electric cars currently-, the authors have studied how state of the art technologies can be used in the relatively new field of collaborative and Human centred robotics. Multiple transmission systems have been considered, among others redundant actuators (both static and kinematic) and continuously variable transmissions. Based on these findings and the experience of the research group on customised planetary gear trains for Human Limb Assistance and Replication, an extensive review of existing redundant actuators is presented in combination with an alternative transmission system which does not need any auxiliary gear transmissions and hence can be lighter and more compact than state of the art drivelines for Human centred robotics. A calculation was performed -including the efficiency model presented by Müller- which shows the high potential of this type of dual-motor actuator.

Small Tooth Number Difference Planetary Gear Drive with a Crank and Oscillating Block Inputting Mechanism

2011 ◽  
Vol 52-54 ◽  
pp. 1268-1273 ◽  
Author(s):  
Jian Kun Cui
Keyword(s):  
Potential Application ◽  
Planetary Gear ◽  
Transmission Mechanism ◽  
Gear Pair ◽  
Gear Drive ◽  
Small Tooth ◽  
Tooth Number ◽  
New Type ◽  
Internal Gear ◽  
Block Mechanism

A new mechanism construction for small tooth number difference planetary gear drive is developed in which the planet wheel is guided by a planar crank and oscillating block mechanism. The sizes of linkage are design dexterously to get an approximate circumference linkage curve so that the engaging condition of internal gear pair can be satisfied. The trajectory of the inner gear center motion is analyzed and its error comparing with a standard circle is calculated to avoid movement interference. The movement of inner gear is study particularly to deduced formula of instantaneous transmission ratio. Despite observable fluctuation of output speed, this new type of gear transmission mechanism still has potential application value in situation with large ratio and low input speed. A hand drive winch prototype using the mechanism is also illustrated in this paper.

Animation of Deformable Bodies with Quadratic Bézier Finite Elements

2014 ◽  
Vol 33 (3) ◽  
pp. 1-10 ◽  
Author(s):  
Adam W. Bargteil ◽  
Elaine Cohen
Keyword(s):  
Finite Elements ◽  
Deformable Bodies

scholarly journals Contact mechanics for soft robotic fingers: modeling and experimentation

Robotica ◽  
2012 ◽  
Vol 31 (4) ◽  
pp. 599-609 ◽  
Author(s):  
Sadeq H. Bakhy ◽  
Shaker S. Hassan ◽  
Somer M. Nacy ◽  
K. Dermitzakis ◽  
Alejandro Hernandez Arieta
Keyword(s):  
New York ◽  
Contact Mechanics ◽  
Weighted Least Squares ◽  
Theory Of Elasticity ◽  
Contact Theory ◽  
Nonlinear Contact ◽  
Different Types ◽  
Least Squares Curve Fitting ◽  
Almost All ◽  
Power Law Equation

SUMMARYHuman fingers possess mechanical characteristics, which enable them to manipulate objects. In robotics, the study of soft fingertip materials for manipulation has been going on for a while; however, almost all previous researches have been carried on hemispherical shapes whereas this study concentrates on the use of hemicylindrical shapes. These shapes were found to be more resistant to elastic deformations for the same materials. The purpose of this work is to generate a modified nonlinear contact-mechanics theory for modeling soft fingertips, which is proposed as a power-law equation. The contact area of a hemicylindrical soft fingertip is proportional to the normal force raised to the power of γcy, which ranges from 0 to 1/2. Subsuming the Timoshenko and Goodier (S. P. Timoshenko and J. N. Goodier, Theory of Elasticity, 3rd ed. (McGraw-Hill, New York, 1970) pp. 414–420) linear contact theory for cylinders confirms the proposed power equation. We applied a weighted least-squares curve fitting to analyze the experimental data for different types of silicone (RTV 23, RTV 1701, and RTV 240). Our experimental results supported the proposed theoretical prediction. Results for human fingers and hemispherical soft fingers were also compared.

Study on Calculations of Geometric Dimensions and Modification Coefficients of Planetary Gear Reducer of Less Tooth Difference with Biasing Crankshaft Based on Matlab

2013 ◽  
Vol 644 ◽  
pp. 298-303
Author(s):  
Qiang Xu ◽  
Qi Sheng Xu ◽  
Dao Yi Xu
Keyword(s):  
Planetary Gear ◽  
Optimal Choice ◽  
The Other ◽  
Gear Pair ◽  
Calculation Results ◽  
Internal Gear ◽  
Center Distance ◽  
Choice Method

Different formula characteristics of internal gear pair with few teeth difference of planetary gear reducer with biasing crankshaft were compared, and the restricted conditions satisfied by them when meshing were set forth. On this basis, the relationships of modification coefficients, tooth addendum coefficient and the center distance were studied, the optimal choice method for modification coefficient based on matlab for the smallest meshing angle was proposed, and verified with living example, at the same time the effect of the different step lengths on calculation results was researched. The results showed that the optimum method is accurate, and avoids the disadvantages of the other optimal choice methods.

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