Introduction to gear trainsintroduction to gear trains. 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. If the arm is the input and the planet is the output, the overall gear ratio is 31 3. Epicyclic gear trains assume one set of gears planets rotates about a central gear. Epicyclic gear train analysis by the tabular method. Table 1 comparison of parallel shaft vs epicyclic gear trains.
Epicyclic gear train gear machines free 30day trial. Pdf the mechanical efficiency of epicyclic gear trains. The gear train consists of five external gears and 4 internal annulus gears, including sun and planet gears forming an epicyclic gear train. Tabular method for epicyclic gear trains watch more videos at.
Simple train three or more wheels connected in series. Compound train an intermediate shaft carries two wheels connected in series. Theory of machines is an applied science of the relationships between geometry and relative motion of the parts of the machine, and concerns to the forces which. Let, ta number of teeth on gear a, and tb number of teeth on gear b. A carrier connects the centers of the two gears and rotates to carry one gear, called the planet gear, around the other, called the sun gear. R is the angular speed of the arm, equal to the input angular speed. The tabular method is easier and hence mostly used in solving problems on epicyclic gear. The velocity ratio of an epicyclic gear train is determined by the following methods. The following two methods may be used for finding out the velocity ratio of an epicyclic gear train. Tabular method, epicyclic gear train, assignment help. Create table where each column is an element in the above. 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. 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.
Epicyclic planetary gear system 3d cad model library. Gear train numericals solved and explained, epicyclic gear train numericals solved, gear train tabular method, reverted gear train problems solved, gear tr. Kinematic and dynamic simulation of epicyclic gear trains. Their report presented a method to evaluate the dynamic load increment due to gear. An epicyclic gear train and its associated terminology the general expressions pertaining to the gear train are given below. Technique for examing epicyclic gear box krish gupta, ajay sharma amity university, aset, noida, india abstract this paper presents a method for analyzing epicyclic gearboxes by evaluating the speeds, torques and efficiency of the external elements in epicyclic gear mechanisms, as well as the total ratios of the gear box. The structure of an epicyclic gear the sun wheel, the planet wheels, the annulus and the spider. Following are the different types of gear trains, depending upon the arrangement of wheels. For the love of physics walter lewin may 16, 2011 duration.
The derivation for gearing ratios between sun gear, planet carrier and ring gear motions are given in the attached excel file. Another class of gear train has wide application, the epicyclic or planetary train. A simple epicyclic gear train consists of a sun gear s in figure 1. Problem no 2 on epicyclic gear train gear trains kinematics of machinery theory of machines duration. With the rotation of each element of the gear train in hand, the overall gear ratio becomes easy. We use the method introduced in epicyclic ratio calculation for determining the final gear ratio of an epicyclic gear train. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear.
Jul 11, 2015 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 gear will make 3 rotations on its axis in cw sense. Algebraic method a compound epicyclic gear train internal type consists of two coaxial s 1 and s 2 sun gear a, an arm h, three planetary gears b,c,and e and an annular gear d as shown in fig wheel a has 10 external teeth, b,c and e have 12 external teeth. Let ta number of teeth on gear a, and tb number of teeth on gear b. Design, load analysis and optimization of compound. The best general method for solving epicyclic gear trains is the tabular method, since it does not contain hidden assumptions like formulas, nor require the work of the vector method. In this lecture i have discussed about the numerical problem on simple epicyclic gear train from theory of machines in hindi. Velocity ratio for epicyclic train velocity ratio of epicyclic gear train is the ratio of the speed of the driver to the speed of the driven or follower. Advantages of planetary gear system planetary gear system has lots of advantage as compared to traditional gearboxes 1. Aug 25, 2017 for the love of physics walter lewin may 16, 2011 duration. 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. In the practical work, resonance and deformation may occur in the planetary gear train, they will affect transmission stability and accuracy, and even. 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.
Jan 17, 2018 problem no 2 on epicyclic gear train gear trains kinematics of machinery theory of machines duration. A fixedring epicyclic gear train is required to have an overall ratio of 5. Pdf design, load analysis and optimization of compound. The gear b meshes with gear a and has its axis on the arm at o2, about which the gear b can rotate. Gear trains theory of machines engineering reference.
Designing compound epicyclic gear trains for maximum speed at high. All the components are modelled in catia to check the assembly and the. The first step is to isolate the epicyclic train, separating the gear trains for inputs and outputs from it. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes. Design of machinery an introduction to the synthesis and. Theory of machines is an applied science of the relationships between geometry and relative motion of the parts of the machine, and concerns to the forces which act on those parts. A thorough understanding of the sometimes difficult material is. Technique for examing epicyclic gear box krish gupta, ajay sharma amity university, aset, noida, india abstract this paper presents a method for analyzing epicyclic gearboxes by evaluating the speeds, torques and efficiency of the external elements in epicyclic gear mechanisms, as well as the total ratios of. 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. 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. In all cases, if d is known, f 1 d, or, if f is known, d 1 f. Sun gear engages one gear of the chain and can be fixed or free to rotate.
Epicyclic gearing requires a stepbystep process to make it work, and some of the steps are not necessarily intuitive. The mechanical efficiency of epicyclic gear trains. Therefore the axes of both the gears are also fixed relative to each other. Example 6 figure shows a compound epicyclic gear train. The arm b is free to turn on the shaft and makes one ccw rotation. In the numerical of simple epicyclic gear train i have found out or calculated. Hi, this is a simple, configurable, epicyclic planetary gear train created in creo parametric 3. A network theory for variable epicyclic gear trains. Iif the calculated result is negative, the driver and follower will rotate in opposite directions. Two inputs are needed to obtain a predictable output. Scribd is the worlds largest social reading and publishing site.
Planetary gear train with compact structure, small volume, large capacity, large range of transmission and high efficiency, is a kind of advanced gear transmission mechanism. An elementary gear train is composed of 3 parts or nodes. Velocity ratios of epicyclic gear train the following two methods may be used for finding out the velocity ratio of an epicyclic gear train. In the numerical of simple epicyclic gear train i have found out or calculated the speed. What is the advantage and disadvantage of a epicyclic gear. It will be extremely useful to american engineers since it stresses the efficiencies of new and existing transmission designs and provides concise guide rules as well as worksheets.
Epicyclic train article about epicyclic train by the. This method is particularly useful for the synthesis and design of novel automotive planetary transmissions, where very early in the design. For a more involved epicyclic gear train example, please refer to the epicyclic gear train example section. The input gear has 20 teeth and the output gear has 100 teeth. Planetary epicyclic gear ratios equations and calculators. 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. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves around the center of the other. 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 following two methods may be used for finding out velocity ratio of an epicyclic gear train. First of all, let us suppose that the arm is fixed. Planetary gear system could be used to secure higher gear ratio in compact space. This example shows an epicyclic gear drive with overall ratio of 256. The stationary gear sun gear or ring gear can be referred to as the central gear.