Compound train an intermediate shaft carries two wheels connected in series. It is interesting to note that coefficient of friction is variable and it depends on operating conditions. We use the method introduced in epicyclic ratio calculation for determining the final gear ratio of an epicyclic gear train. In an epicyclic gear train, the axes of the shafts, over which the gears are mounted, move relative to a fixed axis. In the first three types of gear trains, the axes of the shafts over. Introduction to gear trainsintroduction to gear trains. There are several possibilities for epicyclic arrangements. Hey guys here i have solve this an example of epicyclic gear train in medical in a very simplified form so that you can understand it much better and can apply the same concept to. In this example, gear 1 and gear 3 are on the same axis. In an epicyclic gear train, the axis of at least one of the gears also moves. In the lever analogy, an entire compound planetary gear train can usually be. A thorough understanding of the sometimes difficult material is facilitated through the use of both schematic and symbolic diagrams. Note that gear shifting in a gear transmission consists. 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.
The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can. Calculate the torque to accelerate simple gear trains. Pdf the paper presents an epicyclic gear train dynamic mathematical model including. 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. With increase in pitch line velocity, lubricant used should be less viscous in order to min. Figure 1 shows the free body diagrams of two meshing gears.
Pdf epicyclic gear train dynamics including mesh efficiency. All the components are modelled in catia to check the assembly and the. Jun 12, 2016 hey guys here i have solve this an example of epicyclic gear train in medical in a very simplified form so that you can understand it much better and can apply the same concept to every problem. Jan 23, 2015 here is a picture of a typical gear box. As the carrier rotates, planets rotate on planet gear shafts while orbiting the sun.
Design, load analysis and optimization of compound epicyclic. This reverted technology is very much useful when the power is to be transmitted within the less space. Problem no 1 on epicyclic gear trains gear trains kinematics of machinery theory of machines duration. But in case of epicyclic gear trains, the axes of the shafts on which the gears are mounted may move relative to a. Using lever analogy diagrams in teaching compound planetary. The conventional gear trains described in the previous sections are all onedegreeoffree. 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. Jun 17, 2019 epicyclic gear train nptel pdf merge sijthre.
These drives receive an unusually clear treatment because at dr. The name epicyclic is derived from the curve traced. A gear train hav ing a relative motion of axes is called planetary or an epicyclic gear train. Epicyclic gear systems can be divided into three types. Simple train three or more wheels connected in series. The wheels d and e rotate together on a pin fixed to the arm g. The number of teeth on wheels c, d, e and f are 35, 65, 32 and 68 respectively.
The book is profusely illustrated and analyzes many applications. The earliest known reference to gear trains is in a treatise by hero of. 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. Riveted gear train gear ratio is calculated similar to compound gear train. 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. Apr 24, 20 compound gear train in a compound gear train at least one of the shafts in the train must hold two gears. Jan 17, 2018 problem no 1 on epicyclic gear trains gear trains kinematics of machinery theory of machines duration. Gear train apparatus a solid base mounts an epicyclic arm, which is free to rotate about a fixed pivot point on bearings. A pgt has been represented by its functional schematic, structural and kinematic graph.
Example for, sun and planet gear is a compound epicyclic gear train. The epicyclic gear train is useful for transmitting highvelocity ratio with a gear of moderate size and in less space. A gear train is usually made up of two or more gears. Epicyclic gear train nptel pdf automatic transmission has not better fuel economy. When pinion is the driver, it results in step down drive in which nptl output speed. Advantages of planetary gear system planetary gear system has lots of advantage as compared to traditional gearboxes 1. Reverted gear trains are a type of compound gear trains in which input and output shafts are on the same axis. For a more involved epicyclic gear train example, please refer to the epicyclic gear train example section. A gear train is a combination of gears used to transmit motion from one shaft to another. Example 6 figure shows a compound epicyclic gear train, gears s1 and s2 being rigidly attached to the shaft q. A gear whose axis itself is revolving is called a planetary gear. Finally, the ring is the internal gear that meshes with the planets.
Design, load analysis and optimization of compound. Describe epicyclic gear boxes solve gear box ratios. On completion of this short tutorial you should be able to do the following. Pdf on aug 18, 2014, amar kumar and others published epicyclic gear train. In some epicyclic gear trains, we may find two or more. Calculate the input and outputs speeds and torques of gear boxes. Solid mechanics tutorial gear systems this work covers elements of the syllabus for the edexcel module 21722p hncd mechanical principles outcome 3. Gear trains theory of machines engineering reference with. Compound gear trains are used when large changes in speed or. Two inputs are needed to obtain a predictable output. These gear arrangements give different speed ratio options. What is the advantage and disadvantage of a epicyclic gear.
In absence of lubricant additives and antifriction coating, gears will be subjected to direct friction. 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. 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 also known as planetary gear consists of two gears mounted so that the center of one gear revolves around the center of the other. 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. It is assumed that the student is already familiar with the following concepts. Types of gear train and velocity ratio calculation techminy. Planetary gear system could be used to secure higher gear ratio in compact space. The wall mounted single epicyclic gear train consists of a single stage epicyclic gear train for laboratory demonstration of gear. 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.
With the rotation of each element of the gear train in hand, the overall gear ratio becomes easy. Compound gears are simply a chain of simple gear trains with the input of the second. In epicyclic gear train, different types of gear are used like spur gear, helical gear, bevel gear and many more. 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. Mullers discovery of their perfect analogy to the simple epicyclic drive 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. They are used to achieve high gear ratio within limited space. When there is only one gear fitted on each shaft, then this type of gearing system named simple 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. Design of machinery an introduction to the synthesis and. The gear have more than one gear on the shaft in any epicyclic gear trains, there is called compound epicyclic gear train.
Epicyclic definition of epicyclic by the free dictionary. 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. 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. Compound gear trains are used when large changes in speed or power output are needed and there is only a small space between the input and output shafts. Another class of gear train has wide application, the epicyclic or planetary train. The gear train consists of five external gears and 4 internal annulus gears, including sun and planet gears forming an epicyclic gear train. Epicyclic gearing was used in the antikythera mechanism, circa 80 bce, to adjust the.
So reverted gear train may be called as a compund gear train but all compound gear train can not be a reverted gear train. We have generally 4types of gear trains, and those are. The gear b meshes with gear a and has its axis on the arm at o2, about which the gear b can rotate. When there are three or more planets, as is the usual case, care must be made to make sure the teeth of both planets can engage. Pdf design, load analysis and optimization of compound. Gear c compound epicyclic gear trainsun and planet gear in an epicyclic gear train, as shown in figure, the wheel c is keyed to the shaft b and wheel f is keyed to shaft a. Types of gear train simple, compound, reverted, epicyclic. 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. Interface shear strength in mixed lubrication can be given by. In this paper, graph theory is used for the study of epicyclic gear trains or planet gear trains e. If the arm is the input and the planet is the output, the overall gear ratio is 31 3.
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