The epicyclic gear train family in general has a central sun gear which meshes with and is surrounded by planet gears. 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. So in the case of a simple gear train, the speed ratio is. N1, n2, n3 speed of gears 1 driver, gear 2 idler, gear 3 driven respectively.
Only were the simple planetary gears discussed in these studies, the research on the encased planetary gears with power flow was rarely published. Design of machinery an introduction to the synthesis and. 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. 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. In an epicyclic train the axis of at least one of the gears also moves relative to the frame. Epicyclic gear train solution techniques with application. The epicyclic gear train is a mechanical transmission device. In an epicyclic gear train, the axis of at least one of the gears also moves. Determine the train ratio for the epicyclic train shown below. Design a gear train that is composed of spur gears that has a gear ratio of 29.
In this paper, graph theory is used for the study of epicyclic gear trains or planet gear trains e. Each gear in a simple gear train is mounted on its own shaft. Oct 04, 2018 in this video solve numerical problem related to epicyclic and sun and planet gear train. We present here a simple, methodical procedure for determining the final gear ratio of an epicyclic gear train. The gear trains is having only one gear on each shaft is known as simple gear train. When there is only one gear on each shaft, as shown in fig. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves. Difference simple gear, compound gear and elliptical gear. In the first three types of gear trains, the axes of the. The schematic of a conventional planetary gear train is shown in fig.
Types of gear train simple, compound, reverted, epicyclic. Sep 30, 2012 the types of gear train are given below. The velocity ratio and train value in simple gear train with idler gear. It is stated that the simple planetary gear train consisting. Simple train three or more wheels connected in series. Then another important factor you should know about and that is train value. Gear trains theory of machines engineering reference. What are some applications of the simple gear trains.
A gear train hav ing a relative motion of axes is called planetary or an epicyclic gear train. Gears are cut to exhibit a 25 pressure angle and the module must be 3 mm throughout the train. Epicyclic gear systems can be divided into three types. A gear train is a combination of gears used to transmit motion from one shaft to another. Design, load analysis and optimization of compound epicyclic. Epicyclic gear train solution techniques with application to.
Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes. Usually when two gears mate, they rotate opposite to each other. The sun gear, ring gear and planet carrier all rotate about the same axis. Assume, the motion transmit between gear 1 to gear 3 through idler gear 2. R is the angular speed of the arm, equal to the input angular speed. 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.
The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can rotate. 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. A planetary gear train is very much like our own solar system, and thats how it gets its name. 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. In contrary, humandesigned gearing systems are versatile, ranging from simple, compound, reverted, to epicyclic gear trains 33. Free body diagrams of gear trains american society for. Gear trains theory of machines engineering reference with.
About the gear efficiency to a simple planetary train. A planetary or epicyclical gear trains comprises of one or more planet gears revolving around a sun gear. Planetary or epicyclic gear train epicyclic gear train. The outermost gear, the ring gear, meshes with each of the planet gears. Both compound and internal or external planet gears are considered as well as the paired planet gears. Epicyclic gear train with a basic transmission ratio of 1. The input gear has 20 teeth and the output gear has 100 teeth. L where a gear a and the arm c have a common axis at o 1 about which they can rotate. A pgt has been represented by its functional schematic, structural and kinematic graph.
In this regard, manmade machinery provides us a rich yet more. A thorough understanding of the sometimes difficult material is facilitated through the use of both schematic and symbolic diagrams. Design and load analysis of and optimization of compound. A planetary gear train is a little more complex than other types of 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. This method is extremely procedural, which is appropriate since use of intuition is often quite futile when applied to complex gear trains. Introduction to gear trainsintroduction to gear trains. Planetary gear trains are one of the main subdivisions of the simple epicyclic gear train family. When the two gear are mating together, they rotating in opposite direction to each other. It has the peculiarity of having two degrees of mobility, like the differential, that is to say it associates three trees with different rotation speeds with a single mathematical relationship. Design, load analysis and optimization of compound.
Finally, the ring is the internal gear that meshes with the planets. In an epicyclic gear train, the axes of the shafts, over which the gears are mounted, move relative to a fixed axis. Example 6 figure shows a compound epicyclic gear train, gears s1 and s2 being rigidly attached to the shaft q. The overall gear ratio of a simple planetary gearset can be calculated using the following two equations, representing the. In a compound epicyclic gear train as shown pdfinancialcorp com in the figure, has gears. In this gear there is more than one gear on the shaft which is rigidly fix and mashed with the gear on another shaft forming gear train. Simple gear train consist two or more gear but only one gear is mounted on each shaft and these shafts are rigidly fixed or not movable. 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. The advantages of the epicyclic gear train are as follows. These drives receive an unusually clear treatment because at dr. 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. These are used in various automobiles and by this the effort of the driver will reduce and it increases comfort. The simple and complex epicyclic gear trains 4 figure 4.
Please start with the tutorial for shaft calculation to see how to introduce geometry and supports for single shafts. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can. Following are the different types of gear trains, depending upon the arrangement of wheels. In the first three types of gear trains, the axes of the shafts over.
Two simply mesh gears are known as simple gear train. Types of gear train and velocity ratio calculation techminy. For simple gear train, compound gear train and reverted. It is the ratio of the speed of driven gears to the speed of the driver gears is known as the train value.
Pdf the mechanical efficiency of epicyclic gear trains. A presentation on epicycle gear train linkedin slideshare. Stoeckicht adapted epicyclic gears for aircraft and marine applications. The ring gear is stationary and the arm rotates at 1 rpm. Only one gear in each shaft and there is a relative motion between shaft axis.
One example of two gear train is shown in the image below. 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. In epicyclic gear train, different types of gear are used like spur gear, helical gear, bevel gear and many more. In a planetary train at least one of the gears must revolve around another gear in the gear train. Structure and analysis of planetary gear trains sciencedirect. Jul 11, 2015 epicyclic gear train an epicyclic gear train,the axes of the shafts, over which the gears are mounted, may move relative to a fixed axis. A twostage planetary gear stage is defined using the program. Another class of gear train has wide application, the epicyclic or planetary train. As the carrier rotates, planets rotate on planet gear shafts while orbiting the sun. The book is profusely illustrated and analyzes many applications. When pinion is the driver, it results in step down drive in which nptl output speed. Each gear train consists of a sun gear in the centre, three planet gears, a planet linkage and an internal or ring gear. New design and improvement of planetary gear trains.
Simple gear train is a type of gear train which is used to transmit motion and power from one shaft to another shaft. The velocity ratio of an epicyclic gear train is determined by the following methods. Fbd of a planetary gear train a planetary gear train is a gear train that allows the input and output shaft to be coaxial. Planet gears are just idle gears from the force perspective, and the fbd is shown in fig. Jun 07, 2017 in this video, we have discussed how to tackle questions related to gear train, how to make the necessary table and reach the desired conclusion. 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. Apr 24, 20 the simple gear train is used where there is a large distance to be covered between the input shaft and the output shaft. Mullers discovery of their perfect analogy to the simple epicyclic drive trains. If there is only one gear mounted on each shaft, the gear train is known as simple gear train. Pdf the paper presents an epicyclic gear train dynamic mathematical model including mesh. In the first three types of gear trains, axes of shafts over which the gears are mounted are fixed relative to each other 112320.
All the components are modelled in catia to check the assembly and the. The planet gears are mounted on shafts that turn in planet carrier and meshes with both the sun gear and the ring gear. Difference simple gear, compound gear and elliptical gear train. Compound train an intermediate shaft carries two wheels connected in. What is epicyclic gearbox main components, working and. There are several possibilities for epicyclic arrangements. The speeds of two of the trees to know that of the third. These gear trains are also used in bicycle for controlling power during pedaling. When driver gear is rotated in a clockwise direction, driven gear will rotate in anticlockwise direction. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear. Gear train to be used in the human powered vehicle teams design effort 2 figure 2. The name epicyclic is derived from the curve traced. Compound train an intermediate shaft carries two wheels connected in series.
Planetary or epicyclic gear train gear train mechanical. Epicyclic gear train nptel pdf automatic transmission has not better fuel economy. Thus the conventional gear train is simply a special case of the more complex epicyclic train, in which its arm is held stationary. Epicyclic gear train of the lower arrangement of quadrant i in figure 3 5 figure 5. When examining simple gear trains, it is necessaryto decide whether the output gear will turn faster, slower, or the same speed as the input gear. Pdf epicyclic gear train dynamics including mesh efficiency. Types of gear trains following are the different types of gear trains, depending upon the arrangement of wheels. We have already discussed that in an epicyclic gear train, the axes of the shafts, over which the gears are mounted, may move relative to a fixed axis. In this simple example of an epicyclic train, the only gear left to take an output.