For heat transfer across a composite slab with materials having different thermal conductivity, study the following statements. The concept of a gear train is a rather simple one. The velocity ratio of an epicyclic gear train is determined by the following methods. Govindaraju,ssec 25 reverted gear train the driver and driven axes lies on the same line. These are used in speed reducers, clocks and machine tools. I am a mechanical engineer, with great thirst to learn more, apply more, and work hard more.
The image to the left shows a schematic of a reverted gear train. Following are the different types of gear trains, depending upon the arrangement of wheels. The pinion has 21 teeth and the gear has 126 teeth with a diametral. In a reverted epicyclic gear train, the arm a carries two gears b and c and a compound gear d e. A calculator for designing a multistage compound gear train. Spur gears with 20 pressure angle are used, with 16 teeth on each of the small gears and 48 teeth on each of the larger gears. Consequently, the dimensions of the sun gear would be onethird of the pinion of a parallel shaft geartrain designed to transmit an equivalent torque. 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. Reverted spur gear train 3d cad model library grabcad. Find the speed and direction of gear c when gear b is fixed and the arm a makes 100 r. In this article, you will learn gear, types of gears and gear trains. Provides teeth counts from any given overall ratio. In which of the following type of gear train, the first gear and last gear are coaxial. But in simple reverted gear train the direction of rotation of input and output shaft is same.
Ppt gear trains powerpoint presentation free to view. The gear b meshes with gear e and the gear c meshes with gear d. Ppt gear trains powerpoint presentation free to view id. The output should deliver the power at a rotational speed in the range of 280 to 300 revmin. Reverted gear train as shown in figure, when gear 1 and 2 are rotate in opposite direction. Chapter 4 gear trains theory of machine, mechanical. In a reverted gear train, the motion of the first gear and the last gear is same. When theres a gear problem everything can come to stop because of this its important for you to understand how gears work in order to keep them working. Compound gear trains are used when large changes in speed or power output. Design, load analysis and optimization of compound epicyclic. Gear trains mechanical engineering mcq questions and. Govindaraju,ssec 24 reverted gear train concentric input output shafts dr. Mechanical analysis gear trains city, university of london.
Reverted gear has two or more rigidly fixed gears of different size and has different number of teeth on the same shaft with same axis of rotation and same angular velocity. A gearbox is to be designed with a compound reverted. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves. A simple reverted gear train consists of two shafts each of which. A gearbox is to be designed with a compound reverted gear train that transmits 25 horsepower with an input speed of 2500 revmin. Thus the conventional gear train is simply a special case of the more complex epicyclic train, in which its arm is held stationary. This type of gear train is used in applications like clock where we need two coaxial or colinear shafts to rotate in same direction but at. Another class of gear train has wide application, the epicyclic or planetary train. Reverted gear train output shaft is concentric with the input shaft. The number of teeth on gears b, c and d are 75, 30 and 90 respectively. Theory of machine study notes hand written tom free. The image to the left shows a schematic of a reverted geartrain. The diametral pitch to be used for the gears is 9 teethinch. The constants that i am given is the amount of teeth each gear has, the diameter of the gears, the input torque, speed in rpm and voltage of the dc motors, and finally the time it takes the toy car to travel 10 feet when its in the slow speed high torque setting.
Educational, industrial design, machine design, tags. For the gear train shown below, determine the train value, output speed, output direction, output torque, and output power. Such a combination is called gear train or train of toothed wheels types of gear trains following are the different types of gear trains, depending upon the arrangement of wheels. Sometimes, two or more gears are made to mesh with each other to transmit power from one shaft to another. The gear 3 which is now the second driver drives the gear 4 i. 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. Reverted gear is use in compound gear train which is a difference between simple gear train and reverted gear train. This chapter will explore the theory of gear tooth action and. Compound reverted gear design project by obadah yaghi on prezi. Although my true skills shine in the mechanical design and heat transfer fields, i have a strong interest towards integrating mechanical devices with electronics. Thus we see that in a reverted gear train, the motion of the first gear and the last gear is like. 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.
Two inputs are needed to obtain a predictable output. Gear trains theory of machines engineering reference. Gear 2 and 3 are mounted in same shaft the gear 3 rotate in same direction as that of gear 2. In an epicyclic gear train, the axes of the shafts, over which the gears are mounted, move relative to a fixed axis.
A gear train is a combination of gears used to transmit motion from one shaft to another. A planetary gear train having four gears that are arranged as two externalinternal pairs, in which the two external gears are connected to form a cluster which rotates around a rotatable eccentric, and within the respective internal gears. Used in clocks,lathes to rearrange the speed output. Sep 15, 2015 the constants that i am given is the amount of teeth each gear has, the diameter of the gears, the input torque, speed in rpm and voltage of the dc motors, and finally the time it takes the toy car to travel 10 feet when its in the slow speed high torque setting. The four velocity ratios of the coplanar reverted gear train loop 800, are as follows, with the power stage ratio k1 representing the product abcd, where a is the number of teeth on the pinion gear 814 a, b is the number of teeth on the inner surface of the ring gear 818. Epicyclic gear train application the reverted gear trains are used in automotive transmissions, lathe back gears, industrial speed reducers, and in clocks where the minute and. Compound planetary gears involve one or more of the following three types of structures. This reverted gear train consists of 4 double spur gears each with a gear ratio of 3. Gears 4 and 1 are in line, and gears 2 and 3 are on the same shaft. Us4014224a speed differential planetary gear train. Reverted gear train are the compound gear train in which both the axis of the driver and the driven shaft are coaxial. 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. Types of gears classification of gears types of gear trains.
Nov 25, 2017 usually, gear trains that are used in automobiles are planetary gear trains. The number of teeth on the gear is ias1997 a 32 b 30 c16 d 15 2. A simple reverted gear train consists of two shafts each of which carry multiple compound spur gears. Design a compound, reverted gear train with spur gears that has a ratio of 25. 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. Design of machinery an introduction to the synthesis and. Let t1 number of teeth on gear 1, r1 pitch circle radius of gear 1, and n1 speed of gear 1 in r. In this simple example of an epicyclic train, the only gear left to take an output. Stoeckicht adapted epicyclic gears for aircraft and marine applications. It is a compound gear with, two gearspairs, and a special condition that makes the total number of teeth of the first gearpair equals the number of teeth of the secondgearpair, when the module is the same. 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. Certain relations between parameters of the four gears provide high efficiency.
Apr 04, 20 reverted gear train when the axes of the first gear i. A gearbox is to be designed with a compound reverted gear. 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. L where a gear a and the arm c have a common axis at o 1 about which they can rotate. Gear train, modification, gear ratio, direction, spur gear. Problem no 2 on epicyclic gear train gear trains kinematics of machinery theory of machines duration. A compound gear train with gears p, q, r and s has number of teeth 20, 40, 15 and 20, respectively. Works on home computers pc or mac as well as smartphones and tablets. However, the velocity ratio for each pair of gears must then be multiplied together to calculate the. Gear train simple compound reverted with numerical. In other gear trains such as simple gear train, compound gear train and reverted gear train, gear shaft axis is fixed or not movable, but in epicyclicplanetary gear trai. Oct, 2017 gear train is the combination of two or more than two gear to transfer the power from one shaft to another shaft. Pdf gear ratios for compound gear trains of minimum weight.
Consequently, the dimensions of the sun gear would be onethird of the pinion of a parallel shaft gear train designed to transmit an equivalent torque. It is required to obtain large speed reduction within a small space. This type of arrangement is used in clocks and in simple lathe where back gears are used to give a slow speed to the chuck. In the first three types of gear trains, the axes of the shafts over. Types of gear train and velocity ratio calculation techminy. In the case of the reverted gear train, the driver and the last gear are coaxial. Additionally, for the reverted compound gear train, applicability of the solution obtained is evaluated for the special case in which the. Gear trains mechanical engineering mcq questions and answers. A compound gear consists of two gears of different pitch diameters attached to one another.
Determine the numbers of teeth and pitch diameters for each gear. But in case of epicyclic gear trains, the axes of the shafts on which the gears are mounted may move relative to a. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can rotate. The train will end up being reverted gear 1 and 3 will be in line and gear 2. A reverted gear train is shown in figure given below, it should be noted that gear 1 and the gear 4 are mounted on the driver and the driven shaft respectively, whose axes are collinear. Gear ratios for compound gear trains of researchgate. Introduction to gear trainsintroduction to gear trains. The input gear has 20 teeth and the output gear has 100 teeth. Used to change the direction of rotation or to connect two shafts at a distance. Gear trains are widely used in all kinds of mechanisms and machines, from can openers to aircraft carriers. Gears q and r are mounted on the same shaft as shown in the figure below.
Epicyclic gear train epicyclic means one gear revolving upon and around another. 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. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can. It is a compound gear with, two gearspairs, and a special condition that makes the total number of teeth of the first gear pair equals the number of teeth of the second gear pair, when the module is the same. A standard gear has outside diameter of 96mm and module 3 mm. A gear train is a mechanical system formed by mounting gears on a frame so that the teeth of the gears engage. What are the different types of gear trains used in.
A reverted gear train is one where first and last gears are on the same axis. Reverted gear train when the axes of the first gear i. It should be pointed out that six planets do not necessarily give a gearing twice the capacity of a similar. Jan 17, 2018 problem no 2 on epicyclic gear train gear trains kinematics of machinery theory of machines duration. Types of gear train simple, compound, reverted, epicyclic. A gear train is a mechanical system formed by mounting gears on a frame so the teeth of the gears engage. Usually, gear trains that are used in automobiles are planetary gear trains. Note that a zero velocity input to the arm merely makes a conventional train out of the epicyclic train as shown in figure 932a. Gears q and r are mounted on the same shaft as shown in. The first and last gear are mounted on same axis of rotation in shaft is known as reverted gear trains.