New design and improvement of planetary gear trains faydor l. Epicyclic gear train nptel pdf an intermittent rotation i is superimposed on to a constant rotation c generated from the cylinder comb shaft in the epicyclic gear train. Like a compound gear train, planetary trains are used when a large change in speed or power is needed across a small distance. Zoltan levai received 9 february 1968 abstract both compound and internal or external planet gears are considered as well as the paired planet gears. Pdf design optimization of planetary gear trains under. A gear train is a combination of gears used to transmit motion from one shaft to another. Equation and calculators to determine ratios of planetary or epicyclic gear assemblies. An efficient method of achieving high reduction ratios in minimum space is the use of planetary gearing. This results in different ratios being generated by the. Generally, singlestage epicyclic gear trains are more efficient than equivalent parallel shaft gear trains because. Planetary or epicyclic gear train gear train mechanical. Planetary gear trains are one of the main subdivisions of the simple epicyclic.
Helical gearing, in which the teeth are cut at an angle with the axis of rotation, was developed after spur gearing and has the advantages that has the smoother action and tends to be trainw fig. Epicyclic gear train nptel pdf merge helical gearing, in which the teeth are cut at an angle with the axis of rotation, was developed after spur gearing and has the advantages that has the smoother action and tends to be trainw fig. A joint venture by iisc and iits, funded by mhrd, govt of india. This planetary gear train consists of a sun gear yellow, planet gears blue supported by the. Having more teeth in mesh, not shifting the load so abruptly, also reduces the noise level. This type of transmission are used by skoda,toyota, lexus, etc epicyclic gearing planetry gearing. The gear wheel transmitted motion between one shaft to another shaft, so the multiple set of gear transmit motion from single main gear to various revolving parts is known as gear train. Gear trains simple, compound and epicyclic gear trains. Asok kumar mallik department of mechanical engineering iit kanpur. Epicyclic gearbox epicyclic gear trains are used to get the various gear ratios. Nptel syllabus kinematics of machines video course s. Introduction to machine design, methodology, strength, rigidity, fracture, wear, and material considerations in design, use of standards, selection of materials and processes. There are four different ways that a planetary train can be hooked up.
Planetary gear trains pdf planetary gear is one of the epicyclic gear, which is a gear system consisting of. One of these planets meshes with the sun gear, the other planet meshes with the ring gear. Introduction to epicyclic gear train working and advantages and disadvantages of the epicyclic gear train. This video is part of the content developed by nptel. These gears are usually thought of as high speed gears.
Planetary epicyclic gear ratios equations and calculators. It is stated that the simple planetary gear train consisting. Solid mechanics tutorial gear systems this work covers elements of the syllabus for the edexcel module 21722p hncd mechanical principles outcome 3. Epicyclic gear train is a special type of gear train which is used to transmit motion and power from one shaft to another shaft. The total mechanical loss is then given as the sum of losses from all gear meshes and bearings. Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer gears, or planet gears, revolving about a central, or sun gear. D rotation of driver per revolution of follower or the driven gear or pulley. Gear trains image from simon fraser university image from jtekt torsen na, inc. 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. Simple gear train compound gear train reverted gear train epicyclic gear train in the first three types of gear trains, the axes of the shafts over which the gears are mounted are fixed relative to each other. The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc. Some epicyclic gear trains employ two planetary gears which mesh with each other. Epicyclic gearing also called as planetary gearing.
In simple, compound and reverted gear train, gear shaft axis is fixed or not movable but in epicyclic gear trains, the shaft axes are not fixed means the shaft axis is movable. Please start with the tutorial for shaft calculation to see how to introduce geometry and supports for single shafts. In the first three types of gear trains, axes of shafts over which the gears are mounted are fixed relative to each other 112320. It is also the goal of this work to dimension the epicyclic gear train to. Litvin, alfonso fuentes, daniele vecchiato, and ignacio gonzalezperez university of illinois at chicago chicago, illinois 606077022 summary the development of new types of planetary and planetary face gear drives is proposed. Planetary or epicyclic gear train epicyclic gear train. Compound train an intermediate shaft carries two wheels connected in. At least one wheel not only rotates about its own axis but also rotates about some other axis automatic gearboxes typically use one or more compound planetary gear sets having two sun gears and two sets of intermeshing planet gears. Epicyclic gear train nptel pdf in the first three types of gear trains, the axes of the shafts over which the gears are mounted are. Types of gear train and velocity ratio calculation techminy. Kinematic analysis of synchromesh, machine tool gear box, differential gear box self study 3. A twostage planetary gear stage is defined using the program.
The epicyclic gear train is useful for transmitting highvelocity ratio with a gear of moderate size and in less space. On completion of this short tutorial you should be able to do the following. Thus, it is not difficult to get the velocity ratio of the gear train in figure 76b. In the first three types of gear trains, the axes of the shafts over which the gears are mounted are fixed relative to each other. Foot operated 2 speed and reverse epicyclic transmission footbrake, 1908 for 19 yrs 9 million were made. Hypoid gear this is a deviation from a bevel gear that originated as a special development for the automobile industry. In this paper, graph theory is used for the study of epicyclic gear trains or planet gear trains e. In some cases, such as the automotive differential, one input is. The planet gear are mounted on a moveable arm carrier. The epicyclic gear first analysed here have the following components. With involute profile of gears, only one contact position experiences pure rolling. The following two methods may be used for finding out the velocity ratio of an epicyclic gear train. Plane t a r y gear tra i n s consis t o f the follo w i n g. Epicyclic gear train nptel pdf merge the total mechanical loss is then given as the sum of losses from all gear meshes and bearings.
Parts in a epicyclic gearbox sun gear the sun gear is a gear located at the centre of the whole setup and is always meshed with the planetary gears. Epicyclic gear trains are known to provide high power density and have become the gear train of choice for the main power flow in virtually all rotorcraft designs. This accounts for epicyclic gear trains being more quiet than parallel shaft gear trains. A pgt has been represented by its functional schematic, structural and kinematic graph. Yi zhang with susan finger stephannie behrens table of contents. Design of machinery an introduction to the synthesis and. Usually, following two types of lubrication mechanisms are commonly used for gear lubrication. Gear train it is defined as two or more gears are made to mesh with each epicyclic gear train the axes of the shafts over which the geaar are mounted, may move relative to a fixed axis. Gear trains theory of machines engineering reference. The gear train maybe for spur gear, helical gear and spiral gear. Following are the different types of gear trains, depending upon the arrangement of wheels. Introduction to gear trainsintroduction to gear trains.
Epicyclic gear trains are generally used for automatic transmission, overdrives, and final drives. Compound planetary gear train planetary gear train with more than one arm r14 t1t3. Design optimization of planetary gear trains under dynamic constraints and parameter uncertainty. Scribd is the worlds largest social reading and publishing site. Notes on the epicyclic gear train solution techniques with application to tandem bicycling new approach. Types of gear train simple, compound, reverted, epicyclic.
The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can. L where a gear a and the arm c have a common axis at o 1 about which they can rotate. A gear train is usually made up of two or more gears. Theory of machines is an applied science of the relationships between geometry and relative motion of the parts of the machine, and concerns to the forces which. Ring or annular gear ring gear is the biggest gear in terms of size in whole geartrain. Calculation of a planetary gear train this tutorial shows the usage of mesys shaft calculation with shaft systems. However, the second method cannot be applied to the spatial gear trains.
In an epicyclic gear train, the axes of the shafts, over which the gears are mounted, move relative to a fixed axis. But in case of epicyclic gear trains, the axes of the shafts on which the gears are mounted may move relative to a. It acts as a drum or a case for all the others gears. Image from blog of haja sherief image from hpi racing image from proquest image from sandia national labs image from piaget image from fortune, apr. Introduction to epicyclic gear train working and advantages. Another class of gear train has wide application, the epicyclic or planetary train. Structure and analysis of planetary gear trains prof. It require small area during the power transmission and to obtain large speed reduction. Epicyclic gear train nptel pdf automatic transmission has not better fuel economy.
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