Thus we see that in a reverted gear train, the motion of the first gear and the last gear is like. The smallest number of teeth on a spur pinion and gear, onetoone gear ratio, which can exist without interference is np. Find the ratio of the output speed to the input speed. L where a gear a and the arm c have a common axis at o 1 about which they can rotate. In some cases, such as the automotive differential, one input is provided the. The gear train is classified into following types, simple gear train compound gear train riveted gear train epicyclic gear train 1. Gear trains theory of machines engineering reference. Ordinary gear trains have axes, relative to the frame, for all gears comprising the train.
Introduction to gear trainsintroduction to gear trains most of the pictures and animations are from norton design of machinery. A gear train is a mechanical system formed by mounting gears on a frame so that the teeth of the gears engage. Nptel lectures power system protection and switchgear. Recognize different gearing systems and relative advantages and disadvantages between them. Tooth load and torque calculations in epicyclic gear trains.
Gear design objectives understand basic principles of gearing. 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 other. By allowing both the planet carrier and the ring gear to rotate, a differential gear drive is produced, the output speed of one. Compound gear train in this type, two or more gears are. A gear train is a combination of gears which are used for transmitting motion from one shaft to another.
Types of gear train and velocity ratio calculation. The first gear known as the driver has 12 teeth, the second gear called the idler has 16 teeth, and the third gear known. They are available of different make and each has its own characteristic. A twostage planetary gear stage is defined using the program. In an epicyclic gear train, the axes of the shafts, over which the gears are mounted, move relative to a fixed axis. Download nptel course material digital communication book pdf free download link or read online here in pdf. Railway engineering damage to railway engineering liao shuqiao and gu zuoqin i. The optimization is based on a multicriterion technique consisting of. Gear train is nothing but a combination of gears which are used to connect the input shaft to the output shaft. Nptel syllabus kinematics of machines video course s note on the model curriculum prepared by aicte five of the seven topics listed under the heading kinematics of machine belongs to dynamics. A lumpedparameter dynamic model for gear train set in wind turbine is proposed to investigate the dynamics of the speedincreasing gear box. If a number of bodies are assembled in such a way that the motion of one. The epicyclic gear first analysed here have the following components. The gear that is turned by the driver gear is called the driven gear.
Gear trains train of gears widely used on machines to transfer motion from one element to many elements. Yi zhang with susan finger stephannie behrens table of contents. Theory of machine study notes hand written tom free. Types of gear trains basic, formula and numerical problems. 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. 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. If a simple gear train is used to give a large speed reduction, the last gear has to be very large. A gear whose axis itself is revolving is called a planetary gear. Depending upon the type and accuracy of motion desired. Ugears steam locomotive mechanical 3d model of train. Epicyclic gear train is a special type of gear train which is used to transmit motion and power from one shaft to another shaft. A knowledge of the e ects of a gear train is important to the control systems designer. The total mechanical loss is then given as the sum of losses from all gear meshes and bearings. Procedure for optimum design of a twostage spur gear system.
Introduction to gear trainsintroduction to gear trains. In this paper, an optimum design of a twostage spur gear system is performed. In some epicyclic gear trains, we may find two or more planetary gears. The concept of active tilt as a whole has been independently developed by. This text will not deal with the stress analysis aspects of gear design. 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 automatic transmission has not better fuel economy. This is unlike the simple and the compound gear trains where their centres are fixed. Types of gear train simple, compound, reverted, epicyclic. It require small area during the power transmission and to obtain large speed reduction. The gear 3 which is now the second driver drives the gear 4 i. Dr kanakuppi sadashivappa bapuji institute of engineering and technology davangere lecture 25 introduction of gears i welcome you for the series of lecture on gear measurement and at module 7, the following.
The teeth on helical gears are cut at an angle to the face of the gear. A practical approach to the optimization of gear trains with. Provide means of connection and disconnection of engine with rest of power train without shock and smoothly. Nptel course material digital communication pdf book. Gear design national broach and machine division,of lear siegler, inc.
This causes the ring gear to rotate in a direction opposite that of the sun. The various types of mechanical comparators are dial indicator, rack and pinion, sigma. Equation and calculators to determine ratios of planetary or epicyclic gear assemblies. Textile engineering mechanics of textile machinery nptel. 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. Planetary gear trains pdf planetary gear is one of the epicyclic gear, which is a gear system consisting of.
Kinematics of machines nptel online videos, courses iit. The amount of power transmitted depends upon the following factors. Planetary gear trains are one of the main subdivisions of the simple epicyclic. Whenever a change in the speed or torque of a rotating device is needed, a gear train or one of its cousins, the belt or chain drive mechanism, will usually be used.
Planetary epicyclic gear ratios equations and calculators. Jul 03, 2019 when pinion is the driver, it results in step down drive in which the output speed. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Understand geometry of different gears and their dimensional pro perties. Contents of power system protection lecture, iit bombay. In order to achieve the above objective, methodology of design used is explained in next point. A gear is essentially a toothed wheel or cylinder that works in tandem with another gear or gears to transmit motion, or to change speed or direction. The number of teeth for spur gears is given by where k 1f fll1 for fulld tht th08f tbt th d ldepth teeth, 0.
Gear trains are widely used in all kinds of mechanisms and machines, from can openers to aircraft carriers. Small electric motors are usually lowtorque and highspeed and a speedreducing gear train is necessary. Design, load analysis and optimization of compound epicyclic. The law of gearing states that the common normal at the point of contact between a pair of teeth must always pass through the pitch point. Pressure angle is the angle between the pressure line and common tangent to pitch circles. In this lecture, i shall give a brief history of toothed gear invention and development and next something about the gear train, then special sophisticated gearing. Nptel video lectures, iit video lectures online, nptel youtube lectures, free video lectures, nptel online courses, youtube iit videos nptel courses. Bevel gears bevel gears are useful when the direction of a shafts rotatidbhdion needs to be changed they are usually mounted on shafts that are 90 degrees apart b t can be designed to ork at otherdegrees apart, but can be designed to work at other. Transmission lines and em waves nptel online videos. Gears may be classified according to the relative position of the axes of revolution. 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. This chapter will explore the theory of gear tooth action and the design. A gear train is a set or system of gears arranged to transfer rotational torque from one part of a mechanical system to another, with some gear ratio performing a mechanical advantage 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 key facts.
Based on the presented approach, optimization of many different gear train concepts can be performed. Simple gear train a simple gear train uses two gears. Calculation of a planetary gear train this tutorial shows the usage of mesys shaft calculation with shaft systems. When a simple gear train has three meshed gears, the intermediate gear between the driver gear and the driven gear is called an idler gear. As the gear shape becomes more complex, it can become more difficult to manufacture and measure. Epicyclic gearbox epicyclic gear trains are used to get the various gear ratios.
Enable power transmission at varied angles and varied lengths. The tooth numbers are n 2 24, n 3 18, n 5 22, and n 6 64. When the teeths are in mesh, the normal drawn at the point of the teeths in mesh of the gears always passes. Read online nptel course material digital communication book pdf free download link book now. Following are the different types of gear trains, depending upon the arrangement of wheels. An idler gear does not affect the gear ratio velocity ratio between the driver gear and the driven gear. 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 refer to systems of two or more meshing gears. The righthand purple gear in the train is actually made in two parts, as shown above. Kinematic analysis of synchromesh, machine tool gear box, differential gear box self study 3. Gear train analysis it is very common to use a gear train following a fractionalhorsepower motor in servo positioning applications.
Introduction to mechanisms carnegie mellon school of. By this time, the canadian lrc design had become the first active tilting train to enter full commercial service, starting with via rail in 1981. To find more books about gear trains pdf nptel, you can use related keywords. In the simplest form, the crash gear box, a collection of spur gears were arranged to give different ratios of input to output speed and in the case of the reverse gear, change the direction of the output rotation. Please start with the tutorial for shaft calculation to see how to introduce geometry and supports for single shafts. Gear ratio is numbers of teeth of larger gear to smaller gear.
When pinion is the driver, it results in step down drive in which nptl output speed. When two teeth on a helical gear system engage, the contact starts at one end of the tooth and gradually spreads as the gears rotate, until the two teeth are in full engagement. Another class of gear train has wide application, the epicyclic or planetary train. For example, commonly used epicyclic gear train, for the same purpose that it can create two output speeds from one input speed is in automobile differential. 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. Beijing to shanhaiguan, tianjin to pukou, tongxian to tuozitou and tianjin to jixian and more than 100 branch lines including tangshan to zunhua, hangu to. Epicyclic gear trains are generally used for automatic transmission, overdrives, and final drives. 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. The advantage of a compound gear train over a simple gear train is that a much larger speed reduction from the first shaft to the last shaft can be obtained with small gears. If the mating gear has more teeth than the pinion, that is. Design of machinery an introduction to the synthesis and. Highlights the paper presents one practical approach to gear train optimization. Introduction rolling cylinders the fundamental law of gearing gear tooth nomenclature gear types simple gear trains compound gear trains reverted gear trains epicyclic or planetary gear trains examples 2.
Gear trains simple, compound and epicyclic gear trains. Nptel nptel online certification course course on spur. Gear surfaces coated with boundary additive or antifriction. A small gear and a larger gear are connected together, one on top of the other. This was the first time i hit a home run with my 12years old son anthony jr. Gate 2019 mechanical engineering syllabus contains engineering mechanics, mechanics of materials, theory of machines, vibrations, machine design, fluid mechanics, heattransfer, thermodynamics, engineering materials, casting, forming and joining processes, machining and machine tool operations, metrology and inspection, computer integrated manufacturing, production planning and control. The epicyclic gear train has these components, it has got planet gear which is.
Feb 23, 2017 join facebook group for more latest videos. Gears are machine elements that transmit motion by means of successively engaging teeth. A gear can be defined as a toothed wheel which, when meshed with another toothed wheel with similar configuration, will transmit rotation from one shaft to another. Usually, following two types of lubrication mechanisms are commonly used for gear lubrication. 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. Recognize the unorthodox ways gears can be used in different mot ion systems. Unit 3 power transmission devices devices structure 3.
Backlash prevention strategies should accomodate gear inaccuracies. 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. Provide a varied leverage between the engine and the drive wheels provide means to transfer power in opposite direction. I welcome you for the series of lecture on gear measurement and at module 7, the following topics are covered in this module. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can.
Gear trains theory of machines engineering reference with. One is that the bushing needs to be wider to t over the cap on the pinion. The same gear train may consist of a few spur gears. Planetary gear trains example for the speed reducer shown, the input shaft a is in line with output shaft b. This is achieved by modeling each rigid gear body as a system of 3 equations, the input and output gears as one linear equation each, and then modeling the connection between gears as another linear equation derived from newtons second law. According to me, some of the best videos for mechanical are. Simple gear train in this type, there is only one gear is mounted on each shaft. Gear trains image from simon fraser university image from jtekt torsen na, inc. 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.
Gear trains often consist of multiple gears in the train, as shown in the next two figures. One of the most common uses of gear trains is in the gear boxes of cars. In gear train, combination of two or gears are used to transmit power. Compound planetary gear train planetary gear train with more than one arm r14 t1t3. Ugears steam locomotive i would recommend this to a friend. Original software for gear train optimization named gto was developed. Understand gear trains and how to calculate ratios. Let t1 number of teeth on gear 1, r1 pitch circle radius of gear 1, and n1 speed of gear 1 in r. This gradual engagement makes helical gears operate much more smoothly and quietly than spur gears. This video leads students through using linear algebra to model a gear train. Gears is a positive drive which transmits exact velocity ratio from one shaft to another shaft, gear drive is used when the distance between driver and follower is very less, when two or more gears are made to mesh with each other to transmit power from one shaft to another, the combination is called gear trains.
Thus a gear train is a set or system of gears arranged to transfer rotational torque from one part of a mechanical system to another. 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. Pressure line is the common normal at the point of contact of mating gears along which the driving tooth exerts force on the driven tooth. Usually for a speed reduction in excess of 7 to 1, a simple train is. Which are the best and worst video lectures made by the. The belts or ropes are used to transmit power from one shaft to another by means of pulleys which rotate at the same speed or at different speeds. D rotation of driver per revolution of follower or the driven gear or pulley. The rockerbogie design has no springs or stub axles for each wheel, allowing the rover to climb over obstacles, such as rocks, that is up to twice the wheels diameter in size while keeping all.
Pdf me6401 kinematics of machinery kom books, lecture. Gear trains linearity videos stem concept videos mit. Gear trains pdf nptel, gear trains nptel pdf download, gear trains nptel lectures, gear and gear train nptel pdf, gear trains, gear trains theory, gear trains problems, gear trains pdf theory of machine, nptel gear train pdf, gear trains pdf theory of machine for diploma. But in case of epicyclic gear trains, the axes of the shafts on which the gears are mounted may move relative to a. Types of gear train and velocity ratio calculation techminy.
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