Introduction to epicyclic gear train working and advantages. Compound planetary gears involve one or more of the following three types of structures. The planet gears are mounted on shafts that turn in planet carrier and meshes with both the sun gear and the ring gear. Nov 12, 2017 problem no 1 on epicyclic gear trains gear trains kinematics of machinery theory of machines duration. Pdf notes on the epicyclic gear train solution techniques. Types of gear train simple, compound, reverted, epicyclic. All 34 types can be derived from one general form of the simple planetary gear train. When there is only one gear fitted on each shaft, then this type of gearing system named simple gear trains. Apr 25, 2020 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 gears are mounted, may move relative to a fixed axis. Each gear train consists of a sun gear in the centre, three planet gears, a planet linkage and an internal or ring gear.
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. The gear train is classified into following types, simple gear train compound gear train riveted gear train epicyclic gear train 1. Pdf the paper presents an epicyclic gear train dynamic mathematical model including mesh efficiency, bearingsseals losses and inertial. The ring gear is stationary and the arm rotates at 1 rpm. Compound gear train in this type, two or more gears are. 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. In this project, we use gear type of transmission system, which is designed depending upon the. Gear surfaces coated with boundary additive or antifriction. It is used as a transmission system to get various speed ratios in forward as well as in reverse. 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. Pdf epicyclic gear train dynamics including mesh efficiency. This design can produce large gear ratios in a small space and are used on a wide range of applications from marine gearboxes to electric screw drivers. In the first three types of gear trains, the axes of the shafts over which the gears are mounted are fixed relative to.
The development of new types of planetary and planetary facegear drives is proposed. It is interesting to note that coefficient of friction is variable and it depends on operating conditions. Types of gear train and velocity ratio calculation techminy. The book is profusely illustrated and analyzes many applications. There are several possibilities for epicyclic arrangements.
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. A thorough understanding of the sometimes difficult material is facilitated through the use of both schematic and symbolic diagrams. The following two methods may be used for finding out the velocity ratio of an epicyclic gear train. These drives receive an unusually clear treatment because at dr. A gear train is usually made up of two or more gears. Pdf kinematic nomographs of epicyclictype transmission. Sep 30, 2012 the types of gear train are given below. 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. 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. The following two methods may be used for finding out the velocity ratio of. This transmission system can be screw type or gears type.
Khk offers for free the gear technical data book in pdf format. Advantages of planetary gear system planetary gear system has lots of advantage as compared to traditional gearboxes 1. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear. Components, working principle, advantages, disadvantages, and applications pdf by mohammed shafi may 2, 2020 may 8, 2020. Epicyclic gear systems can be divided into three types. The name epicyclic is derived from the curve traced.
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. Pdf on aug 18, 2014, amar kumar and others published epicyclic gear train mechanism find, read and cite all the research you need on. Following are the different types of gear trains, depending upon the arrangement of wheels. A differential is a gear train with three shafts that has the property that the rotational speed of one shaft is the average of the speeds of the others, or a fixed multiple of that average. The gear have more than one gear on the shaft in any epicyclic gear trains, there is called compound epicyclic gear train. 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 gears are mounted, may move relative to a fixed axis. By fixing one of the coaxial members and using the remaining two for input and output, three types of simple singlestage epicyclic gearing are possible. A new methodology for the enumeration of feasible clutching sequences for a given epicyclic gear mechanism egm is presented using the kinematic nomographs of epicyclic type transmission mechanisms. Interface shear strength in mixed lubrication can be given by. Mullers discovery of their perfect analogy to the simple epicyclic drive trains. Simple train three or more wheels connected in series. To understand gear ratio we suggest you first read.
When pinion is the driver, it results in step down drive in which nptl output speed. An epicyclic gear train is a coaxial speed reducer or increaser stage comprised of a sun gear, planet gears, and a ring gear townsend 1992. The ratio attained from the gear train depends on the component that has its rotational motion constrained or controlled. Pdf the mechanical efficiency of epicyclic gear trains. The advantage of epicyclic gear train is that, it can get very high or very low velocity ratio compared to simple gear trains and compound gear trains. Solid mechanics tutorial gear systems this work covers elements of the syllabus for the edexcel module 21722p hncd mechanical principles outcome 3. Epicyclic gear systems can achieve high velocity ratios with a small number of gears. Types of gears classification of gears types of gear trains. All the components are modelled in catia to check the assembly and the. Two inputs are needed to obtain a predictable output.
Gear trains theory of machines engineering reference with. Introduction to gear trainsintroduction to gear trains. New design and improvement of planetary gear trains. Another class of gear train has wide application, the epicyclic or planetary train. Planetary or epicyclic gear train epicyclic gear train. 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. The mechanical efficiency of epicyclic gear trains. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can rotate. One is that the bushing needs to be wider to t over the cap on the pinion.
As the carrier rotates, planets rotate on planet gear shafts while orbiting the sun. In gear train, combination of two or gears are used to transmit power. In an epicyclic gear train, the axes of the shafts, over which the gears are mounted, move relative to a fixed axis. Design of machinery an introduction to the synthesis and. Nov 23, 2017 it is the oldest types of gearbox used, in sliding mesh gearbox the gears of main shaft and layshaft are not in mesh i. 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 very useful for learning about gears and gearing. Notes on the epicyclic gear train solution techniques with application to tandem bicycling new approach. We have generally 4types of gear trains, and those are. Design, load analysis and optimization of compound. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves. Determine the train ratio for the epicyclic train shown below. Gears 4 and 1 are in line, and gears 2 and 3 are on the same shaft. Basic gear axis for planetary gear train mechanism. Compound train an intermediate shaft carries two wheels connected in series. Compound train an intermediate shaft carries two wheels connected in. Example for, sun and planet gear is a compound epicyclic gear train.
L where a gear a and the arm c have a common axis at o 1 about which they can rotate. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes. Types of gears gear and its types mechanical gears. The train will end up being reverted gear 1 and 3 will be in line and gear 2. 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. Finally, the ring is the internal gear that meshes with the planets. The sun gear, ring gear and planet carrier all rotate about the same axis. An epicyclic gear train, the axes of the shaft, over which the gears are mounted, move relative to a fixed axis. In this article we will discuss how to calculate gear ratio, speed and torque for various gear train.
A new methodology for the enumeration of feasible clutching sequences for a given epicyclic gear mechanism egm is presented using the kinematic nomographs. Epicyclic gear train nptel pdf automatic transmission has not better fuel economy. Here wheel a and arm c have a common axis at o1 about which they can rotate. The gear train consists of five external gears and 4 internal annulus gears, including sun and planet gears forming an epicyclic gear train. 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. It is a wellknown fact that one can get 111, velocity ratios of six different values having only one planetary gear train p. 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. Components, working principle, advantages, disadvantages, and applications pdf by mohammed shafi may 2, 2020 may 8, 2020 epicyclic gearbox is also known as planetary gearbox or planetary gear train or epicyclic gear train. Usually when two gears mate, they rotate opposite to each other. Gear ratio is the ratio of output and input number of teeth on a shaft. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can. A gear train is a combination of gears used to transmit motion from one shaft to another.
Types of gear trains following are the different types of gear trains, depending upon the arrangement of wheels. 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. Planetary gear system could be used to secure higher gear ratio in compact space. Generally, these are called planetary, star, and solar. On completion of this short tutorial you should be able to do the following. Gear trains theory of machines engineering reference. With certain types of compound arrangements ratios of 2000.
Epicyclic gearbox is also known as planetary gearbox or planetary gear train or epicyclic gear train. Gear basic theory of machine interview question and answers helical gear advantages,disadvantages and application combination of gearless transmission with rods and epicyclic gear train epicyclic gearbox diagram, working, advantages of epicyclic gearbox gear train types, diagram, design calculation what is gear motor. What is the advantage and disadvantage of a epicyclic gear. If there is only one gear mounted on each shaft, the gear train is known as simple gear train. Jun 17, 2019 epicyclic gear train nptel pdf merge sijthre. What is epicyclic gearbox main components, working and. They are used to increase or decrease the speed or torque of the output shaft. A gear or cogwheel or going gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order. Dec 05, 2017 an epicyclic gearbox is an automatic type gearbox in which parallel shafts and gears arrangement from manual gear box are replaced with more compact and more reliable sun and planetary type of gears arrangement and also the manual clutch from manual power train is replaced with hydro coupled clutch or torque convertor which in turn made the. The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc. The schematic of a conventional planetary gear train is shown in fig. A simple epicyclic or planetary gear train is shown the figure.
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