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. Also different methods like tabulation and formula methods are discussed which are used to solve the questions based on planetary gear train. Epicyclic gear train nptel pdf merge friction losses can be divided into two major categories. Apr 04, 20 epicyclic gear train in an epicyclic gear train, the axes of the shafts, over which the gears are mounted, may move relative to a fixed axis. This lesson tells about basics of planetary gear train.
Jul 18, 2017 a gear train is a combination of gears used to transmit motion from one shaft to another. Epicyclic gear train solution techniques with application. Epicyclic gearing requires a stepbystep process to make it work, and some of the steps are not necessarily intuitive. The epicyclic gear first analysed here have the following components. What is the advantage and disadvantage of a epicyclic gear. Planetary gear system could be used to secure higher gear ratio in compact space. A thorough understanding of the sometimes difficult material is. Theory of machines 1 for gate aspirants 17 lessons 2 h 31 m. Provide a varied leverage between the engine and the drive wheels provide means to transfer power in opposite direction. Epicyclic gear train solution techniques with application to. Two or four parameters model gear construction or scalar and vectorial power split. Following are the different types of gear trains, depending upon the arrangement of wheels. In an epicyclic gear train, the axis of at least one of the gears also moves.
Epicyclic gear train free download as powerpoint presentation. 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. If the arm a is fixed the wheels s and p constitute a simple train. Calculation of a planetary gear train this tutorial shows the usage of mesys shaft calculation with shaft systems. This method is extremely methodical, which is appropriate since use of intuition is quite futile with an epicyclic gear train such as the following example. If a simple gear train or compound gear train is attached to the epicyclic gear train, do not include it in the analysis and treat it as part of a separate simple gear train. If the arm is the input and the planet is the output, the overall gear ratio is 31 3. A gear train is a combination of gears used to transmit motion from one shaft to another. Example for, sun and planet gear is a compound epicyclic gear train. Usually, following two types of lubrication mechanisms are commonly used for gear lubrication. Users may download and print one copy of any publication from the public portal for the. Gear trains train of gears widely used on machines to transfer motion from one element to many elements. Publishers pdf, also known as version of record includes final page, issue and. It is a mathematical equation that tells how many values can vary and can help in the first three types of gear trains, the axes of the shafts over which the gears are mounted are ger relative to.
Apr 08, 2019 epicyclic gear train nptel pdf download n is the gears teeth number, the sign depends on the type of gear and, in sequence is for external gears. The following two methods may be used for finding out the velocity ratio of an epicyclic gear train. Mathematics a circle whose circumference rolls along the circumference of a fixed. Planetary gear trains are one of the main subdivisions of the simple epicyclic. Enable power transmission at varied angles and varied lengths. The derivation for gearing ratios between sun gear, planet carrier and ring gear motions are given in the attached excel file. Hi, this is a simple, configurable, epicyclic planetary gear train created in creo parametric 3. The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc. Since the speed ratio or velocity ratio of gear train is the ratio of the speed of the driver to the. Epicyclic definition of epicyclic by the free dictionary. For a more involved epicyclic gear train example, please refer to the epicyclic gear train example section. In case there is a third gear there will be 3 trains and then 3 equations. Circumferential velocities in a complex gear train have 3. Working out planetary gear turns ratios working out the gear ratio of a planetary gear train can be.
Asok kumar mallik department of mechanical engineering iit kanpur. R is the angular speed of the arm, equal to the input angular speed. Right an example of an epicyclic gear sketch lecture. A network theory for variable epicyclic gear trains citation for published version apa.
To define a train, consider that it has always the arm r, a gear of the planet and a main gear. Find the fixed gear if any and substitute a value of zero for its angular velocity 5. Modelling ensures free choice of state variables, potential pregears and folding. The epicyclic gear train with bevel gears is used in 1.
The following two methods may be used for finding out the velocity ratio of. However if the wheel s is fixed so that arm a can rotate about the axis of s. The computeraided design cad files and all associated content posted to this website are created, uploaded, managed and owned by third party users. Gear train conguration appendix a8 another interesting design aspect is that the gear train reverts back to the axle about which the pinion turns. Problem no 1 on epicyclic gear trains gear trains kinematics of machinery theory of machines duration. A gear train having a relative motion of axes is called a planetary or an epicyclic gear train. Gate problems on planetary or epicyclic gear train duration. 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.
As such, this article aims to provide assistance and guidelines for people designing epicyclic gear trains for the first timeand perhaps, if you will, ease their degree of suffering. Design, load analysis and optimization of compound epicyclic. This video is part of the content developed by nptel, a joint initiative of all iits and iisc. 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. Mar 30, 2016 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. The mechanical efficiency of epicyclic gear trains. These drives receive an unusually clear treatment because at dr.
Planetary epicyclic gear ratios equations and calculators. Textile engineering mechanics of textile machinery nptel. Design, load analysis and optimization of compound. A generic power flow model for compound epicyclic fourspeed gears is presented. In order to achieve the above objective, methodology of design used is explained in next point. In some epicyclic gear trains, we may find two or more planetary gears. N is the gears teeth number, the sign depends on the type of gear and, in sequence is for external gears. A planetary gear train is defined as any gear train containing at least one gear that orbits by rotating about its own axis and also about the axis of an arm, or carrier. From equations i and iv, the holding or braking torque t3 may be obtained. In this lesson, we will study about epicyclic gear trains, planetary gear trains, easy method to solve numerals on epicyclic gear train and holding torque of gears. Iif the calculated result is negative, the driver and follower will rotate in opposite directions. All the components are modelled in catia to check the assembly and the. A thorough understanding of the sometimes difficult material is facilitated through the use of both schematic and symbolic diagrams.
Write down the relative velocity equations on the lhs 4. Introduction to gear trainsintroduction to gear trains. In ptolemaic cosmology, a small circle, the center of which moves on the circumference of a larger circle at whose center is the earth and the circumference of which describes the orbit of one of the planets around the earth. In this case, the planet gears have 12 teeth, the sun gear has 18 and the ring gear has 42 teeth. Advantages and velocity ratio of epicyclic gear train. This is sometimes referred to as conepulley backgearing because of its use within the cone pulleys of certain types of machine tools. It is a mathematical equation that tells how many values can vary and can help in the first three types of gear trains, the axes of the shafts over which the gears are mounted are ger relative to each. Enable speed reduction between engine and the drive wheels in. By using epicyclic gear, different torque speed ratio can be obtained.
Planetary gear trains pdf planetary gear is one of the epicyclic gear, which is a gear system consisting of. A question that i often get is how to work out planetary gears using the gear template generator working out the tooth counts for planetary gears is actually not that complicated, so i initially neglected to mention how to do it. Another class of gear train has wide application, the epicyclic or planetary train. In ptolemaic cosmology, a small circle, the center of which moves on the circumference of a larger circle at whose center is the earth and the. Advantages of planetary gear system planetary gear system has lots of advantage as compared to traditional gearboxes 1.
It is made up of a number of elements which are interconnected to form the train. In all cases, if d is known, f 1 d, or, if f is known, d 1 f. The gear train consists of five external gears and 4 internal annulus gears, including sun and planet gears forming an epicyclic gear train. Planetary gear trains are one of the main subdivisions of the simple epicyclic gear train family. When two or more gears are made to mesh with each other to transmit power from one shaft to another, such a combination is called gear train or train of toothed wheels. Generic power split modelling for compound epicyclic four. Please start with the tutorial for shaft calculation to see how to introduce geometry and supports for single shafts. If a number of bodies are assembled in such a way that the motion of one. The planet gear in figure 23 rotates about a fixed bevel gear at the center of which is the driven shaft. The book is profusely illustrated and analyzes many applications. We use the method introduced in epicyclic ratio calculation for determining the final gear ratio of an epicyclic gear train. Design of machinery an introduction to the synthesis and. For more videos click on playlist link shown below v kinematics of machinery komtom degree. An elementary gear train is composed of 3 parts or nodes.
An epicyclic train is often suitable when a large torquespeed ratio is required in a compact envelope. Often gears are treated as pitch cylinder, which roll together without slip as shown in fig. Types of gear train and velocity ratio calculation techminy. Provide means of connection and disconnection of engine with rest of power train without shock and smoothly. The gear have more than one gear on the shaft in any epicyclic gear trains, there is called compound epicyclic gear train. Planetary or epicyclic gear train epicyclic gear train. Gear surfaces coated with boundary additive or antifriction. With the rotation of each element of the gear train in hand, the overall gear ratio becomes easy. Each element consists of the three components illustrated below. A network theory for variable epicyclic gear trains technische. But in case of epicyclic gear trains, the axes of the shafts. A network theory for variable epicyclic gear trains. Higher value of t f cause scuffing failure of gears. It will be extremely useful to american engineers since it stresses the efficiencies of new and existing transmission designs and provides concise guide rules as well as worksheets.
The stationary gear sun gear or ring gear can be referred to as the central gear. Two inputs are needed to obtain a predictable output. A gear train hav ing a relative motion of axes is called planetary or an epicyclic gear train. Planetary gear ratio calculations this article also available in spanish. 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.
The elementary planetary, or epicyclic, gear train is shown in figure 2, along with the simplified representation to. Epicyclic gear train in an epicyclic gear train, the axes of the shafts, over which the gears are mounted, may move relative to a fixed axis. Mullers discovery of their perfect analogy to the simple epicyclic drive trains. Pdf design, load analysis and optimization of compound. A twostage planetary gear stage is defined using the program. The elementary planetary, or epicyclic, gear train is shown in figure 2, along with the simplified representation to be used for the remainder of this thesis. Gear trains image from simon fraser university image from jtekt torsen na, inc.
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