Epicyclic gear sets are used because they are smaller than offset gear sets since the load is shared among the planed gears. Gear trains mechanical engineering mcq questions and. 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. 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. The book is profusely illustrated and analyzes many applications. The first possible solution i thought would be in a modification to the tabular method used for reverted epicyclic gear trains. Freudenstein i in 1955, gave an appropriate but a numerical method for dimensional synthesis of a four bar linkage.
In case the motion of the planet gear is required directly, the shaft of the planet gear can, for example, be coupled to another shaft output shaft by universal. It require small area during the power transmission and to obtain large speed reduction. The following two methods may be used for finding out the velocity ratio of an epicyclic gear train. Compound train an intermediate shaft carries two wheels connected in series.
Therefore the axes of both the gears are also fixed relative to each other. Unified methods of analysis and synthesis of complex drives are employed throughout, suggesting that further simplifications may be possible through the use of a multivalued logic system which is analogous to the bivalent logic system of digital electronics. This makes them lighter and more compact, versus countershaft gearboxes. Calculation of a planetary gear train this tutorial shows the usage of mesys shaft calculation with shaft systems.
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. Epicyclic or planetary gear analysis projects skilllync. Gear trains theory of machines engineering reference. 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. How to derive the formula for the planetary mechanism gear ratio. A gear train is a combination of gears used to transmit motion from one shaft to another. A thorough understanding of the sometimes difficult material is facilitated through the use of both schematic and symbolic diagrams. Introduction to gear trainsintroduction to gear trains. The name epicyclic is derived from the curve traced. This book presents a clear and concise description of a multitude of revolving gear trains. These drives receive an unusually clear treatment because at dr. Epicyclic gear train in epicyclic gear trains, the axes of the shafts on which the. A fixedring epicyclic gear train is required to have an overall ratio of 5. Newton\s method also known as the newtonraphson method, named after isaac newton and joseph raphson, is a method for finding successively better approximations to the roots or zeroes.
What is the advantage and disadvantage of a epicyclic gear. A compound epicyclic gear train is shown in figure. Gear train problem solving kinematics of machinery. A mechanism which consists of one central gear, one or more planet gears and one arm, carrying the planet gears, can be called an elementary planetary gear train elementary p. Tooth load and torque calculations in epicyclic gear trains. Create table where each column is an element in the above equation for each gear in the planetary gear train each row shows one gear in the train select one gear, sun or ring, as the driver and follow the chain adjoining rows should be gears that are engaged. First of all, let us suppose that the arm is fixed. 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. The sign preceding the gear ratio is positive because the ring gear is internal. The method of the innovative synthesis of the epicyclic gear trains was presented.
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 act on those parts. Tabular method for a unique spur gear differential system. In which the tangential force causes bending stresses on. Epicyclic gearing requires a stepbystep process to make it work, and some of the steps are not necessarily intuitive. Problem no 1 on epicyclic gear trains gear trains kinematics of machinery theory of machines duration. These methods are discussed, in detail, as follows. Problem no 2 on epicyclic gear train gear trains kinematics of machinery theory of machines duration. Epicyclic gear trains have been broadly applied in engineering practice.
A new method of design of epicyclic gear trains scientific. If the sun gear is to have between 10 to 15 teeth, suggest the most appropriate numbers of teeth for each of the constituent gears. Application of the element relations to a complete train is carried out as shown in the example which follows. The gear train maybe for spur gear, helical gear and spiral gear. Let, ta number of teeth on gear a, and tb number of teeth on gear b. The gear train consists of five external gears and 4 internal annulus gears, including sun and planet gears forming an epicyclic gear train. A carrier connects the centres 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. Dynamic analysis of epicyclic gear trains by means of. The structure of an epicyclic gear the sun wheel, the planet wheels, the annulus and the spider.
Pdf the mechanical efficiency of epicyclic gear trains. We use the method introduced in epicyclic ratio calculation for determining the final gear ratio of an epicyclic gear train. Please consider this design as a basis to be customised to your own application. Following are the different types of gear trains, depending upon the arrangement of wheels. 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. 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. This book is designed to meet the objectives of the synthesis and analysis of gear trains. An epicyclic gear train also known as planetary gear consists of two gears mounted so that the centre of one gear revolves around the centre of the other. If the shaft p rotates at rpm clockwise, while the annular a2 is driven in counter clockwise direction at 500 rpm, determine the speed and direction of rotation of shaft q. Software gto provides the required results in a very short time. Simple gear trains, compound gear trains for large speed reduction, epicyclic gear trains algebraic and tabular methods of finding velocity ratio of epicyclic gear trains. A twostage planetary gear stage is defined using the program. This method is extremely procedural, which is appropriate since use of intuition is often quite futile when applied to complex gear. Please start with the tutorial for shaft calculation to see how to introduce geometry and supports for single shafts.
Planetary or epicyclic gear train epicyclic gear train. This method is extremely procedural, which is appropriate since use of intuition is often quite futile when applied to complex gear trains. 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. Planetary gear system could be used to secure higher gear ratio in compact space. Design, load analysis and optimization of compound epicyclic. In this simple example of an epicyclic train, the only gear left to take an output. Gear train numericals solved and explained, epicyclic gear train numericals solved, gear train tabular method, reverted gear train problems solved, gear train tabular method, epicyclic gear. 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. Mar 07, 2016 this book is designed to meet the objectives of the synthesis and analysis of gear trains. We present here a simple, methodical procedure for determining the final gear ratio of an epicyclic gear train. Note that a zero velocity input to the arm merely makes a conventional train out of the epicyclic train as shown in figure 932a. The gear ratio is independent of the size of the intermediate wheels which. In this video solve numerical problem related to epicyclic and sun and planet gear train. The mechanical efficiency of epicyclic gear trains.
Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear. Thediscussed examples illustrate how the presented approach can be extendedfor computing the equivalent inertia of an. Everything you need to print a complete, printable and full functional epicyclic gearing train. Access free textbook solutions and ask 5 free questions to expert tutors 247. Advantages of planetary gear system planetary gear system has lots of advantage as compared to traditional gearboxes 1. For the love of physics walter lewin may 16, 2011 duration. Two forms of planetary gears of the bevel type are shown in figures 23 and 24. A simple epicyclic gear train consists of a sun gear s in figure 1. Planetary epicyclic gear ratios equations and calculators. Later it will be proved that a variator ihhwork has one input haft. Epicyclic gear train gear machines free 30day trial. Tabular method consider an epicyclic gear train as shown in fig.
Also, when configured properly, epicyclic gear sets are more efficient. Subject content is presented in a simple and lucid manner. The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc. The planet gear in figure 23 rotates about a fixed bevel gear at the center of which is the driven shaft.
An epicyclic gear train is a coaxial speed reducer or increaser stage comprised of a sun gear, planet gear s, and a ring gear townsend 1992. Epicyclic gears by mauro caresta 1 epicyclic gears aim of this note is to explain the direct method to solve problems with epicyclic gears the epicyclic gear first analysed here have the following components. D rotation of driver per revolution of follower or the driven gear or pulley. Had it been easy gear train gear p will make 2 rotations for one rotation of gear s. Example 6 figure shows a compound epicyclic gear train, gears s1 and s2 being rigidly attached to the shaft q. Tabular method, epicyclic gear train, assignment help. Algebraic method a compound epicyclic gear train internal type consists of two coaxial s 1 and s 2 sun gear a, an arm h, three planetary gears b,c,and e and an annular gear d as shown in fig wheel a has 10 external teeth, b,c and e have 12 external teeth. A network theory for variable epicyclic gear trains. A presentation on epicycle gear train linkedin slideshare.
Types of gear train and velocity ratio calculation techminy. Introduction principles of mechanisms willis, 1841 is widely considered to be the firs put blication dedicated solely to the field now called kinematics, and discusses analytical modeling of an epicyclic gear train for the. The volume of the gear train with spur gears is reduced by 22. Simple train three or more wheels connected in series. Velocity ratios of epicyclic gear trainthere are two methods of finding out the velocity ratios of epicyclicgear trains1.
A substantial amount of literature is available for planar linkages. The following two methods may be used for finding out velocity ratio of an epicyclic gear train. Gear train numericals solved and explained, epicyclic gear train. Velocity ratios of epicyclic gear train tabular method 112320 dr. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can rotate. 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. Design of machinery an introduction to the synthesis and.
Gear trains theory of machines engineering reference with. The annulus gear has internal teeth and the compound gear is carried by thearm and revolves freely on a pin of the arm h. 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. The paper illustrates the application of a systematic technique for thededuction of dynamic equations of epicyclic gear trains. The resultant forces on the gear tooth are resolve into ents namely tangential force and radial force. Thus the conventional gear train is simply a special case of the more complex epicyclic train, in which its arm is held stationary. The use of theproposed method is particularly amenable in conjuction with proceduresfor the computerized enumeration of geared kinematic chains. In this lecture i have discussed about the numerical problem on simple epicyclic gear train from theory of machines in hindi. Let ta number of teeth on gear a, and tb number of teeth on gear b. Simple gear train the ratio of speed of the driven or follower to the. 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.
In an epicyclic gear train, the axes of the shafts, over which the gears are mounted, move relative to a fixed axis. Mullers discovery of their perfect analogy to the simple epicyclic drive trains. One of the downsides to the tabular method shown on the previous page is that it. Epicyclic definition of epicyclic by the free dictionary. 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. Equation and calculators to determine ratios of planetary or epicyclic gear assemblies. The ratio attained from the gear train depends on the component that has its rotational motion constrained or controlled. The gear will make 3 rotations on its axis in cw sense.
Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which. Attempts are made to serve this purpose by adopting stepbystep procedures to analyse the epicyclic gear trains egts. Velocity ratios of epicyclic gear train the following two methods may be used for finding out the velocity ratio of an epicyclic gear train. Jan 17, 2018 problem no 2 on epicyclic gear train gear trains kinematics of machinery theory of machines duration. I am a novice with tabular gear train solutions and am confused by which method to move forward with in order to solve this. Aug 25, 2017 for the love of physics walter lewin may 16, 2011 duration. L where a gear a and the arm c have a common axis at o 1 about which they can rotate. An epicyclic gear train and its associated terminology the general expressions pertaining to the gear train are given below. Technique for examing epicyclic gear box krish gupta, ajay sharma amity university, aset, noida, india abstract this paper presents a method for analyzing epicyclic gearboxes by evaluating the speeds, torques and efficiency of the external elements in epicyclic gear mechanisms, as well as the total ratios of the gear box. Velocity ratio for epicyclic train velocity ratio of epicyclic gear train is the ratio of the speed of the driver to the speed of the driven or follower.