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 gearing also called as planetary gearing. L where a gear a and the arm c have a common axis at o 1 about which they can rotate. This method is extremely procedural, which is appropriate since use of intuition is often quite futile when applied to complex gear trains. The tool investigated is from atlas copco st series and consists of three main parts.
Epicyclic gear train free download as powerpoint presentation. Advantages of planetary gear system planetary gear system has lots of advantage as compared to traditional gearboxes 1. Gear trains theory of machines engineering reference with. What is the advantage and disadvantage of a epicyclic gear. Introduction to gear trainsintroduction to gear trains. Gear trains theory of machines engineering reference. Reverted gear train when the axes of the first driver and the last driven are coaxial, then the gear train is known as reverted gear train. Mar 30, 2016 epicyclic gear train an epicyclic gear train,the axes of the shafts, over which the gears are mounted, may move relative to a fixed axis. In this method a table is completed first as described below. Power acting on the compound epicyclic gear trains is also varied and graphs are plotted to see the load behavior. Structure and analysis of planetary gear trains prof. Pdf two procedures are presented for obtaining the analytical expression for the efficiency of any planetary gear train. Epicyclic gearset gears 6 an epicyclic gear set has some gear or gears whose center revolves about some point. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes with the planet gears.
Image from blog of haja sherief image from hpi racing. Here is a gearset with a stationary ring gear and three planet gears on a rotating carrier. Planetary gear trains the main problems gathered in a book. Gear train conguration appendix a8 another interesting design aspect is that the gear train reverts back to the axle about which the pinion turns. Compound train an intermediate shaft carries two wheels connected in. Ppt planetary gears powerpoint presentation free to view id. The present work on epicyclic gear trains carries out the design of all the gears, shafts, keys and the loads are calculated for individual gears in the epicyclic gear train system. Planetary gears planetary gear trains are one of the main subdivisions of the simple epicyclic gear train family.
Part of diplomadegree in engineering, new zealand nz. In an epicyclic gear train, as shown in figure, the wheel c is keyed to the. In more cases they carried out a separate problem or particular arrangement of planetary gear train. Litvin, alfonso fuentes, daniele vecchiato, and ignacio gonzalezperez. The planet gears are held to a cage or carrier that fixes the planets in. Driver and driven instrumentality should be in line to avoid further gearing.
In order to achieve the above objective, methodology of design used is explained in next point. In 1588, italian military engineer agostino ramelli invented the bookwheel, a verticallyrevolving bookstand containing epicyclic gearing with two. Design, load analysis and optimization of compound. Information and translations of epicyclic gear train in the most comprehensive dictionary definitions resource on the web. Selection and design of planetary gear trains based on power. We present here a simple, methodical procedure for determining the final gear ratio of an epicyclic gear train. In a reverted gear train, the motion of the first gear and the last gear is same. Design, load analysis and optimization of compound epicyclic. Planetary or epicyclic gear train epicyclic gear train. The epicyclic gear train consists of the sun gear a which is in mesh with the planet gear b. A gear train is a mechanical system formed by mounting gears on a frame so the teeth of the gears engage gear teeth are designed to ensure the pitch circles of engaging gears roll on each other without slipping, providing a smooth transmission of rotation from one gear to the next.
Planetary gear trains are one of the main subdivisions of the simple epicyclic gear train family. Jan 17, 2018 for the love of physics walter lewin may 16, 2011 duration. After a short presentation of the stakes in turboshaft engine transmission gears. Hi, this is a simple, configurable, epicyclic planetary gear train created in creo parametric 3.
This gear has an inner hub c which is fixed to b and in mesh with the fixed ring gear r. K inematic a nalysis of the e picyclic g ear t rain fig. Later on completing this table, the given conditions are applied to find out x and y. Transmission gear an overview sciencedirect topics. Each element consists of the three components illustrated below.
Simple compoundgear train n n n n t t t t r nn nn rr rr. Tabular method, epicyclic gear train, assignment help. In an epicyclic or planetary gear train, several spur gears distributed evenly around the circumference run between a gear with internal teeth and a gear with external teeth on a concentric orbit. The name epicyclic is derived from the curve traced. It is shown that for any planetary gear train pgt it is possible to find the relationship existing between the transmission ratio of the train and the power. The velocity ratios of simple gear trains in this stage of transmission are as. Another class of gear train has wide application, the epicyclic or planetary train. The gear have more than one gear on the shaft in any epicyclic gear trains, there is called compound epicyclic gear train. Ppt planetary gears powerpoint presentation free to view. But in case of epicyclic gear trains, the axes of the shafts on which the gears are mounted may move relative to a fixed axis. Once x, and y are known, the revolutions of other elements may be estimated as these are. The outermost gear, the ring gear, meshes with each of the planet gears. 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.
R is the angular speed of the arm, equal to the input angular speed. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can. What is the degree of freedom in epicyclic gear train. Calculate the input and outputs speeds and torques of gear. Mullers discovery of their perfect analogy to the simple epicyclic drive trains. Jun 12, 2016 hey guys here i have solve this an example of epicyclic gear train in medical in a very simplified form so that you can understand it much better and can apply the same concept to every problem. Design of machinery an introduction to the synthesis and. D rotation of driver per revolution of follower or the driven gear or pulley. In an epicyclic gear train, the axes of the shafts, over which the gears are mounted, move relative to a fixed axis. Introduction to epicyclic gear train working and advantages and disadvantages of the epicyclic gear train. Best epicyclic gear train in mechanical engineering. The book is profusely illustrated and analyzes many applications. Application of the element relations to a complete train is carried out as shown in the example which follows. A thorough understanding of the sometimes difficult material is facilitated through the use of both schematic and symbolic diagrams.
Planetary gear system could be used to secure higher gear ratio in compact space. Typically, the planet gears are mounted on a movable arm or carrier which itself may rotate relative to the sun gear. The epicyclic gear train with bevel gears is used in 1. Pdf design, load analysis and optimization of compound. The epicyclic gear train family in general has a central sun gear which meshes with and is surrounded by planet gears. Jul 18, 2017 a gear train is a combination of gears used to transmit motion from one shaft to another.
An epicyclic train is often suitable when a large torquespeed ratio is required in a compact envelope. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves. Compound train an intermediate shaft carries two wheels connected in series. The circulation of the spur gear takes place in analogy to the orbiting of the planets in the solar system.
In case there is a third gear there will be 3 trains and then 3 equations. The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc. This was developed as a chart which shows all the favourable conditions for. Each of the epicyclic gear system consists of one sun gear, three planetary gears, one ring gear and carrier. Gear transmission has been widely used in mechanical equipment as one of the most important transmission modes. Advantages and velocity ratio of epicyclic gear train. It is a gear system that consists of one or more outer gear planet gear rotating about a central sun gear. 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 train three or more wheels connected in series. Epicyclic gear train problems and solutions pdf best of all, they are entirely free to find, use and download, so there is no cost or stress at all. However, advances in internal gear manufacturing did not parallel those in external gears, limiting the development of epicy clic gear trains. Jan 06, 2015 two cases 1 dof when the sun is constant and planet is roatating as well as revolving around sun and arm rotating. Planetary epicyclic gear ratios equations and calculators.
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. Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer gears, or planet gears, revolving about a central. A carrier connects the centers of the two gears and rotates to carry one gear, called the planet gear or planet pinion, around the other, called the sun gear or sun wheel. The planet gears are held to a cage or carrier that fixes the planets in there orbit relative to each other. The advantage of this gear train is the possibility to obtain a low gear ratio, that is not permissible by a conventional face gear train. These drives receive an unusually clear treatment because at dr. Gears 4 4 epicyclic gear train epicyclic means one gear revolving upon and around another. Jan 23, 2015 gears 5 5 epicyclic gear train it is the system of epicyclic gears in which at least one wheel axis itself revolves around another fixed axis. This gear train consists of three identical epicyclic gear stages. Epicyclic gear example solution for gear ratio youtube. Example for, sun and planet gear is a compound epicyclic gear train. The gear b meshes with gear a and has its axis on the arm at o2, about which the gear b can rotate.
More complex epicyclic trains may be analysed in a similar manner, but the technique is not of much assistance when the problem is one of gear train design the interested designer is referred to the bibliography. Two inputs are needed to obtain a predictable output. Types of gear train and velocity ratio calculation techminy. Illustrated sourcebook of mechanical components pgs. As early as 1781, james watt patented a sun and planet gear arrangement used in one of his early engines.
It is made up of a number of elements which are interconnected to form the train. On completion of this short tutorial you should be able to do the following. But in case of epicyclic gear trains, the axes of the shafts on which the gears are mounted may move relative to a. Ppt planetary gears powerpoint presentation free to. Introduction to epicyclic gear train working and advantages. The derivation for gearing ratios between sun gear, planet carrier and ring gear motions are given in the attached excel file. Epicyclic gear systems have a long history of industrial use.
There are five distinct advantages to using an epicyclic gear train as opposed to a single load path parallel gear train. This presentation is very useful for the subject theory of machine, topic name. Example solution for a single stage epicyclic gear. A novel twin epicyclic gear train for optimal power sharing. Theory of machines epicyclic gear trains bysheetal bansal air29ies2014. New design and improvement of planetary gear trains faydor l. Epicyclic gear train with bevel gear the bevel gears are used to make a more compact epicyclic system and they permit a very high speed reduction with few 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. They are coupled in a way that the ring gear of the first stage is connected to the sun gear of the second stage and so on. The mechanical efficiency of epicyclic gear trains. Gear transmissions such as bevel and planetary gears are widely used in a many kinds of. Compound epicyclic gear trains compound epicyclic gear trains. Definition of epicyclic gear train in the dictionary.
The analytical expression of the efficiency of planetary gear trains. An epicyclic gear train also known as planetary gear consists of two gears mounted so that the center of one gear revolves around the center of the other. Two gears can only mesh if they have the same circular pitch, diametral pitch or module 22 23 12 12 3 3 n rd r nr d. Describe three types of epicyclic gear boxes solve gear box ratios. Equation and calculators to determine ratios of planetary or epicyclic gear assemblies. 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 epicyclic means one gear revolving upon and around another.
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