Types of gear train and velocity ratio calculation techminy. The gear have more than one gear on the shaft in any epicyclic gear trains, there is called compound epicyclic gear train. This method is extremely methodical, which is appropriate since use of intuition is quite futile with an epicyclic gear train such as the following example. Often gears are treated as pitch cylinder, which roll together without slip as shown in fig.
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. Following are the different types of gear trains, depending upon the arrangement of wheels. Equation and calculators to determine ratios of planetary or epicyclic gear assemblies. Planet gear for each planet gear, we can write nslr as follows. The power is transmitted from gear b to d through the intermediate gear c which revolves freely on a pin. It is interesting to note that coefficient of friction is variable and it depends on operating conditions. If the arm is the input and the planet is the output, the overall gear ratio is 31 3.
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. L where a gear a and the arm c have a common axis at o 1 about which they can rotate. Another class of gear train has wide application, the epicyclic or planetary train. A gear train is a combination of gears used to transmit motion from one shaft to another. 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. Jun 17, 2019 epicyclic gear train nptel pdf merge sijthre. 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 input gear has 20 teeth and the output gear has 100 teeth.
The name epicyclic is derived from the curve traced. The grabcad library offers millions of free cad designs, cad files, and 3d models. In case there is a third gear there will be 3 trains and then 3 equations. 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. Involute spur gears is a free gear designing software for windows.
Join the grabcad community today to gain access and download. 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. Design, load analysis and optimization of compound. 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. A gear train hav ing a relative motion of axes is called planetary or an epicyclic gear train. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can. To define a train, consider that it has always the arm r, a gear of the planet and a main gear. R is the angular speed of the arm, equal to the input angular speed. These drives receive an unusually clear treatment because at dr.
It is extremely simple to use, standalone gear design software using which you can easily design spur gear sets as it is used to design gear sets, you can define number of teeth, profile correction, and segments per flank for individual spur gear. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can rotate. With the rotation of each element of the gear train in hand, the overall gear ratio becomes easy. In this video solve numerical problem related to epicyclic and sun and planet gear train. The gear b meshes with gear a and has its axis on the arm at o2, about which the gear b can rotate. A pgt has been represented by its functional schematic, structural and kinematic graph. But in case of epicyclic gear trains, the axes of the shafts on which the gears are mounted may move relative to a. In this paper, graph theory is used for the study of epicyclic gear trains or planet gear trains e. For a more involved epicyclic gear train example, please refer to the epicyclic gear train example section. The planetary gear set, also known as the epicyclic gear train, is one of the most important and interesting inventions in engineering. The circulation of the spur gear takes place in analogy to the orbiting of the planets in the solar system. Planetary or epicyclic gear gear ratios are the rates at which the selected gears rotate relative the mechanical advantage. The angular speed of the planet carrier can be found since we know the. Pdf the paper presents an epicyclic gear train dynamic mathematical model including.
Mullers discovery of their perfect analogy to the simple epicyclic drive trains. 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. We have generally 4types of gear trains, and those are. This type of dynamometer can be classified as follows. 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. Planetary epicyclic gear ratios equations and calculators. Planetary or epicyclic gear train epicyclic gear train. Pdf epicyclic gear train dynamics including mesh efficiency. Gear surfaces coated with boundary additive or antifriction. 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. It acts as a drum or a case for all the others gears. The book is profusely illustrated and analyzes many applications.
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. 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. Example for, sun and planet gear is a compound epicyclic gear train. The gear train consists of five external gears and 4 internal annulus gears, including sun and planet gears forming an epicyclic gear train.
The conventional gear trains described in the previous sections are all onedegreeof free. Download limit exceeded you have exceeded your daily download allowance. Interface shear strength in mixed lubrication can be given by. 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. Advantages of planetary gear system planetary gear system has lots of advantage as compared to traditional gearboxes 1. New design and improvement of planetary gear trains. To determine the input power and output power of the epicyclic gear system. Epicyclic gear train, planetary gear set, mesh efficiency, modeling. 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. We use the method introduced in epicyclic ratio calculation for determining the final gear ratio of an epicyclic gear train. Objectives to understand the working principle of epicyclic gear system. Epicyclic train article about epicyclic train by the free. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear. Mar 30, 2016 velocity ratios of epicyclic gear train the following two methods may be used for finding out the velocity ratio of an epicyclic gear train.
The epicyclic gear train is useful for transmitting highvelocity ratio with a gear of moderate size and in less space. Planetary kinematics note that point 1 on the planet gear is stationary zero velocity due to noslip assumption note that point 2 on the planet gear has the same velocity as point 2 on the sun gear also due to noslip assumption, which is given by. Jul 03, 2019 epicyclic gear train nptel pdf to excel pdf files kinematic analysis of synchromesh, machine tool gear box, differential gear box self study 3. Design, load analysis and optimization of compound epicyclic. In an epicyclic or planetary gear train, several spur gears distributed evenly around the circumference run between a gear with internal teeth and a gear with external teeth on a concentric orbit. In an epicyclic gear train, the axis of at least one of the gears also moves. An epicyclic gear train consists of two gears mounted so that the centre of one gear revolves the fundamental formula of the planetary gear train with a rotating carrier is obtained by recognizing that. Planetary gear system could be used to secure higher gear ratio in compact space. In an epicyclic gear train, the axes of the shafts, over which the gears are mounted, move relative to a fixed axis.
The number of teeth on wheels c, d, e and f are 35, 65, 32 and 68 respectively. With four core components, calculating the gear ratio of planetary gear systems, also known as epicyclic gear systems, may seem daunting. When pinion is the driver, it results in step down drive in which nptl output speed. Epicyclic gearing also called as planetary gearing. Velocity ratios of epicyclic gear train the following two methods may be used for finding out the velocity ratio of an epicyclic gear train.
Table 1 comparison of parallel shaft vs epicyclic gear trains. The wheels d and e rotate together on a pin fixed to the arm g. Epicyclic gear train, output torque, holding torque. Usually, following two types of lubrication mechanisms are commonly used for gear lubrication. Tabular method consider an epicyclic gear train as shown in fig. Lock the arm and assume other wheel is free to rotate. Jan 17, 2018 problem no 1 on epicyclic gear trains gear trains kinematics of machinery theory of machines duration.
The mechanical efficiency of epicyclic gear trains. 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. Epicyclic gear train dynamics including mesh efficiency core. When there is only one gear fitted on each shaft, then this. Epicyclic gear train nptel pdf merge friction losses can be divided into two major categories.
This is a comprehensive text and reference book for students and teachers of mechanical engineering, for design and research engineers, and for manufacturers and users of gear trains for the transmission of power in industry and transportation. Introduction to epicyclic gear train working and advantages and disadvantages of the epicyclic gear train. Epicyclic gear train nptel pdf automatic transmission has not better fuel economy. Jan 23, 2015 here is a picture of a typical gear box. All the components are modelled in catia to check the assembly and the. With increase in pitch line velocity, lubricant used should be less viscous in order to min. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves. To calculate gear ratio of the epicyclic gear system. The input shaft is the central sun gear 1, and the output. 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 circumference of which describes the orbit of one of the planets around the earth. To determine the power loss of the epicyclic gear system. Pdf the mechanical efficiency of epicyclic gear trains.
In absence of lubricant additives and antifriction coating, gears will be. Pdf epicyclic drive trains download read online free. Epicyclic gearing requires a stepbystep process to make it work, and some of the steps are not necessarily intuitive. Design of machinery an introduction to the synthesis and. Mathematics a circle whose circumference rolls along the circumference of a fixed. Parts in a epicyclic gearbox sun gear the sun gear is a gear located at the centre of the whole setup and is always meshed with the planetary gears. 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. What is the advantage and disadvantage of a epicyclic gear. Introduction to epicyclic gear train working and advantages. In terms of coupled pgts, the torque equilibria at the cutfree couplings are to be consi.
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. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes. Two inputs are needed to obtain a predictable output. Epicyclic definition of epicyclic by the free dictionary. A combination of epicyclic gears, usually connected by an arm, in which some or all of the gears have a motion compounded of rotation about an axis and a translation or revolution of that axis. Example 6 figure shows a compound epicyclic gear train, gears s1 and s2 being rigidly attached to the shaft q. A gear train is usually made up of two or more gears. A thorough understanding of the sometimes difficult material is facilitated through the use of both schematic and symbolic diagrams. Ring or annular gear ring gear is the biggest gear in terms of size in whole geartrain. Higher value of t f cause scuffing failure of gears. Let, ta number of teeth on gear a, and tb number of teeth on gear b. As such, this article aims to provide assistance and guidelines for people designing epicyclic gear trains for the first timeand perhaps, if you will, ease their degree of suffering. After specifying these options, click on redraw option to get visualization of. Pdf on aug 18, 2014, amar kumar and others published epicyclic gear train mechanism find, read and cite all the research you need on.
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