Lock the arm and assume other wheel is free to rotate. Free body diagrams of gear trains american society for. According to mueller, two fundamental planetary gear trains are kinematically equivalent if one gear ratio of a transmission is equal to. The graph theory has been proved to be an effective tool to synthesize and analyze pgts. Planetary gear trains crc press book this book provides comprehensive information for various planetary gear trains, with practical applications and comprehensive references to technical articles. Compound planetary gear 728 a study on optimization of planetary gear trains 729 tablei planetarygeartraincombinations. Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer, or planet, gears or pinions, revolving about a central sun gear or sun wheel. Epicyclic gear trains egts are commonly used in automatic transmission mechanisms to achieve a set of desired velocity ratios 1. In a planetary train at least one of the gears must revolve around another gear in the gear train. It is a gear system that consists of one or more outer gear planet gear rotating about a central sun gear. A twostage planetary gear stage is defined using the program. Design, load analysis and optimization of compound. Plane t a r y gear tra i n s consis t o f the follo w i n g.
Epicyclic gearing also called as planetary gearing. The planetary gear trains are commonly used in automotive transmissions. Teaching planetary gear trains with the aid of nomographs. Gear ratio product of driven teethproduct of driving teeth gear ratio 100 x 100 x 100 20 x 40 x 10 125 alternatively we can say there are three simple gear trains and work ot the ratio for each. Special issue of the 3rd international conference on. A gear whose axis itself is revolving is called a planetary gear.
We use the method introduced in epicyclic ratio calculation trqin determining the final gear ratio of an epicyclic gear train. Planetary gear simulator two facing gears were rotated around slightly different centers, and one drove the other not with meshed teeth but with a pin inserted into a slot on the second. Microsoft powerpoint automatic transmission basics. The gear train in an automobile differential is a common application of gears, but nptell misunderstood by the lay public. Dynamic analysis of planetray gear trains considering. Epicyclic gear trains are known to provide high power density and have. Optimization,planetary gear trains tangential tooth load, wear tooth load, dynamic tooth load, static tooth load i. Introduction to gear trainsintroduction to gear trains. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can rotate. Survey of dynamics of planetary gear trains article pdf available in international journal of materials and structural integrity 14 july 2008 with 678 reads how we measure reads. Table 1 comparison of parallel shaft vs epicyclic gear trains. Pdf planetary gear trains pgt have been widely used in many industries due. L where a gear a and the arm c have a common axis at o 1 about which they can rotate. Free body diagram of the gears forming a planet gear set.
Dc gear motor planetary gear industrial quality 10 pack. Cylindrical gear geometry is the basis for dealing with any. The outermost gear, the ring gear, meshes with each of the planet gears. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear. It is stated that the simple planetary gear train consisting of two central gears, one or more planet gears and one arm, has 34 different types. Layout and free body diagram of a single planetary gear set. On completion of this short tutorial you should be able to do the following. This paper aims to propose a new graph model, which has some merits relative to the existing ones, to represent the structure of pgts. A planetary gear train is a little more complex than other types of gear trains. Kinematic equivalence of planetary gear transmissions muellers book ref. Planetary gear trains pdf planetary gear is one of the epicyclic gear, which is a gear system consisting of.
It was developed under the motto from practice to practice. In some epicyclic gear trains, we may find two or more. Design, modelling and analysis of a 3 stage epicyclic planetary reduction gear unit of a flight vehicle k akhila1 and m amarnath reddy2 corresponding author. An automotive gear differential is a jointfractionated planetary gear train with two degreesoffreedom. The classical lever analogy provides an easy way to study the kine. Introduction special layouts of simple planetary gear trains composed planetary gear trains elements of planetary gear train design list of symbols. Any basic or compound planetary system is defined in terms of rotating elements sun wheels, planet wheels and planet carriers with one rotational degree of freedom each.
Another class of gear train has wide application, the epicyclic or planetary train. New graph representation for planetary gear trains. Users can choose the number of planets, segments per flank, and the number of internal and planet gear teeth. The usefulness of planetary gear trains and the engineering techniques necessary for optimum design are discussed in this paper. The research program covers basic ideas of the design of the proposed gear drives. Planetary gear trains pgts are widely used in machinery to transmit angular velocity ratios or torque ratios. A planetary gear train is very much like our own solar system, and thats how it gets its name. Spur, helical, bevel, worm and planetary gears are all covered, with consideration given to their classification, geometry, kinematics, accuracy control, load capacity and manufacturing. The designs can be exported into dxf and svg files for use in other. Demkowicz texas institute for computational and applied mathematics the university of texas at austin austin, tx 78712 abstract the paper is a continuation of the work presented in 5, aimed at modeling of a. Lightweight design for planetary gear transmissions.
The world of planetary gears planetary gears, which can supply a lot of speed reduction and torque in a small package, have operating characteristics beyond those of fixedaxis gear trains charles. Planetary kinematics note that point 1 on the planet gear is stationary zero velocity due to noslip assumption note that point 2 on the planet gear has the same velocity as point 2 on the sun gear also due to noslip assumption, which is given by. Fbd of a planetary gear train a planetary gear train is a gear train that allows the input and output shaft to be coaxial. The book reflects not only teaching, but also the practical experience of the authors. Usually, an epicyclical gearing systems are employed to achieve high reduction ratio in a small and power. Planetary gear designer is a free program to design simple planetary gears. Design of machinery an introduction to the synthesis and. One of the planetary gearsets from our transmission has a ring gear with 72 teeth and a sun gear with 30 teeth. Department of applied mechanics, university of chemical. Pdf survey of dynamics of planetary gear trains researchgate. Gears and gear drives provides the reader with comprehensive coverage of gears and gear drives. Introduction a planetary or epicyclic gear trains comprises of one or more planet gears revolving around a sun gear. Introduction to epicyclic gear train working and advantages and disadvantages of the epicyclic gear train. Figure 1 shows the free body diagrams of two meshing gears.
Problem no 2 on epicyclic gear train gear trains kinematics of machinery theory of machines duration. Kinematics and statics analysis for power flow planet gear trains. The angular speed of the planet carrier can be found since we know the. R is the angular speed of the arm, equal to the input angular speed. Dimitar petkov karaivanov this book provides comprehensive information for various planetary gear trains, with practical applications and comprehensive references to technical articles. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes. Calculation of a planetary gear train this tutorial shows the usage of mesys shaft calculation with shaft systems. Planetary gear trains are one of the main subdivisions of the simple epicyclic gear train family. The rotational motion of those elements is constrained by some number of permanent gear meshes. If there npetl more than one arm in the planetary gear train.
Sun gear carrier ring gear speed torque direction 1 input output held maximum reduction increase same as input 2 held output input. This book provides comprehensive information for various planetary gear trains, with practical applications and comprehensive references to technical articles. The epicyclic gear train family in general has a central sun gear which meshes with and is surrounded by planet gears. Planet gears are just idle gears from the force perspective, and the fbd is shown in fig. Planetary gear trains provide high power density in comparison to standard parallel axis gear trains. In an epicyclic gear train, the axes of the shafts, over which the gears are mounted, move relative to a fixed axis. A practical method to analyze planetary gear train for speed ratio determination is lever analogy. The planet gear are mounted on a moveable arm carrier. Download planetary gear trains free epub, mobi, pdf ebooks download, ebook torrents download. Using lever analogy diagrams in teaching compound planetary. All 34 types can be derived from one general form of the simple planetary gear train.
Choosing which piece plays which role determines the gear ratio for the gearset. New types of planetary facegear drives the developed facegear drives are shown in figs. Two inputs are needed to obtain a predictable output. Planetary gear trains is the most comprehensive and uptodate work available in this key technical area. Please start with the tutorial for shaft calculation to see how to introduce geometry and supports for single shafts. In the texts chapters, readers can find all the information needed for various types of gear trains, with illustrations and examples. The sun gear fixity was determined by its support stiffness. Planetary gear trains the main problems gathered in a book.
Each of these three components can be the input, the output or can be held stationary. Pdf epicyclic drive trains download read online free. Dynamic contactimpact problems, energy conservation, and planetary gear trains a. Epicyclic gear train, output torque, holding torque. Dynamic contactimpact problems, energy conservation, and. Automatic transmission basics linnbenton community.
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