It implies that the total length of the train has crossed the total length of the object. Design of machinery an introduction to the synthesis and. Higher value of t f cause scuffing failure of gears. Calculating output torque and holding torque for compound gears. 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. A shop owner has approached your design company to make a mechanical toy based on a head turning. R5 combine these linear equations into a matrix equation. Whenever a change in the speed or torque of a rotating device is needed, a gear train or one of its cousins, the belt or chain drive mechanism, will usually be used. Friction losses can be divided into two major categories. Design, load analysis and optimization of compound epicyclic. Solved examples with detailed answer description, explanation are given and it would be easy to understand. Jan 23, 2015 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 will also address the use of epicyclic gear trains as a power coupling in a tandem bike.
To define a train, consider that it has always the arm r, a gear of the planet and a main gear. Problems with britains trains rail transport the guardian. Compound gear train problem why is it so hard physics. Pdf the mechanical efficiency of epicyclic gear trains. This chapter will explore the theory of gear tooth action and. The epicyclic gear train family in general has a central sun gear which meshes with and is surrounded by planet gears. Based largely on the work of robert willis 2, techniques have been provided to find the motion of and forces present in an egt in the most general case. Often gears are treated as pitch cylinder, which roll together without slip as shown in fig.
Procedure 1 write down the two gear trains that share the arm r starting from the input shaft, usually the planet gear is the middle one. 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. 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. Planetary or epicyclic gear train epicyclic gear train. In the numerical of simple epicyclic gear train i have found out or calculated the speed. Problems on trains question and answers with easy solutions in aptitude topic are present here. R5 model the forces and torques in a gear train as a system of linear equations.
Two gears can only mesh if they have the same circular pitch, diametral pitch or module 22 23 12 12 3 3 n rd r nr d. Typically, the planet gears are mounted on a movable arm or carrier which itself may rotate relative to the. Another class of gear train has wide application, the epicyclic or planetary train. A train is said to have crossed an object stationary or moving only when the last coach end of the train crosses the said object completely. In this video i explain about epicyclic gear train and how can we get different different speed ratio by one gear train.
More teething problems on gwrs brand new intercity. 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. The mechanical efficiency of epicyclic gear trains. The outermost gear, the ring gear, meshes with each of the planet gears. Experimental analyses of vibration and noise of faulted.
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 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. Thediscussed examples illustrate how the presented approach can be extendedfor computing the equivalent inertia of an. The input gear has 20 teeth and the output gear has 100 teeth. Plane t a r y gear tra i n s consis t o f the follo w i n g. The ring gear 5 is fixed and the gear 2 is rotating at 60 rpn ccw ccwcounterclockwise and cw clockwise. Usually, following two types of lubrication mechanisms are commonly used for gear lubrication. The use of theproposed method is particularly amenable in conjuction with proceduresfor the computerized enumeration of geared kinematic chains. The driver shaft a rotates at 100 revsmin and the gear has a diameter of 40mm. More teething problems on gwrs brand new intercity express train. Hidaka first studied the problem of load distribution among the planets. This is the aptitude questions and answers section on problems on trains with explanation for various interview, competitive examination and entrance test. On each click on problems on trains quiz question system will tell you where the answers are correct or incorrect in the problems on trains online test.
A planet with 2 gears, gp1 and gp2 1 arm r connected to the input or output shaft 2 main gears g1 and g2 that are in contact with gp1 and gp2 respectively. Other uses for gears how gear ratios work howstuffworks. In an epicyclic gear train, the internal wheels a, b and the compound wheel c and d rotate independently about the axis o. A gear train is a set or system of gears arranged to transfer rotational torque from one part of a mechanical system to another, with some gear ratio performing a mechanical advantage 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 key facts. Kinematics and dynamics of a planetary gear train for robotics 5 gear3a is planet gear adjacent to carrier2a. In the numerical of simple epicyclic gear train i have found out or calculated. Sep 18, 2017 hi all online lectures for engineering students. If a simple gear train is used to give a large speed reduction, the last gear has to be.
There are understandable, simple solutions useful for rrb alp, group d and bank jobs. A carrier connects the centres 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. Calculation of a planetary gear train this tutorial shows the usage of mesys shaft calculation with shaft systems. R is the angular speed of the arm, equal to the input angular speed. An epicyclic gear train is shown schematically in the adjacent figure. Specifically, this thesis will provide a simple solution technique for the general case of a twodegree of freedom 2dof planetary gear train along with new graphical design aids. In epicyclic gear trains, the axes of shafts on which the gears are mounted may move relative to a fixed axis. University, entitled epicyclic gear train solution techniques with application to tandem bicycli ng1, christopher corey has presented a complete design and anal ysis technique for epcyclic gear.
The gear train consists of five external gears and 4 internal annulus gears, including sun and planet gears forming an epicyclic gear train. The sun gear2 on the input shaft is a 20 teeth external gear. Three coaxial members numbered 1a,1b,1c are supported by bearings housed in the forearm. The little gear in the middle is the idler the big gear on the right is the drive gear and the one on the left is the driven gear. All the components are modelled in catia to check the assembly and the.
In this lecture i have discussed about the numerical problem on simple epicyclic gear train from theory of machines in hindi. A gear train is a combination of gears used to transmit motion from one shaft to another. A gear train is a mechanical system formed by mounting gears on a frame so the teeth of the gears engage gear teeth are designed to ensure the pitch circles of engaging gears roll on each other without slipping, providing a smooth transmission of rotation from one gear to the next. Based on the number of degrees of freed om, the epicyclic gear trains can be further categorized as differential and planetary gear trains. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear. Becaue of this page, i prepared myself for train problems in just 20 mins mastguru 5 years ago replied. The owner would like your company to manufacture a shop display that is eye catching for passers. How many gears are required for 3 speed reduction in an.
Design, load analysis and optimization of compound. The advantage of a compound train over a simple gear train is that a much larger. Gear trains are widely used in all kinds of mechanisms and machines, from can openers to aircraft carriers. Mech 314 dynamics of mechanisms april 16, 2011 planetary gear train velocities 1 planetary gears and pitch point gear velocities figure 1. So the absolute speed of a gear is the relative speed with respect to the shaft plus the shafts speed with respect to ground. Introduction to gear trainsintroduction to gear trains. A gear train is a set or system of gears arranged to transfer rotational torque from one part of a mechanical system to another, with some gear ratio performing a mechanical advantage. Find the length of a bridge which a train m long, travelling at 45 km an hour, can cross in 30 secs. Internal ring gear, three planets on spiderarm and the sun gear as semipictorial fig.
The stationary gear sun gear or ring gear can be referred to as the central gear. Planetary gear trains are one of the main subdivisions of the simple epicyclic gear train family. All three are attached to a plate the planet carrier, and they engage the inside of the blue gear the ring instead of the outside. This mock test has 77 aptitude questions, with four choices.
Calculating the input power required for a drive gear in a train. Previous years gate questions on gear trains 200820. The basic 3speed hubs have a single sun gear solidly attached to the middle of the axle. Gear trains theory of machines engineering reference. The asm chart, another form of a state diagram, is shown in figure 7 for this problem. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes. Bevel gear pairs1b2b3band1c2c3c transmit the rotations of the coaxial input links to the endeffector. If the sun gear is to have between 10 to 15 teeth, suggest the most appropriate numbers of teeth for each of the constituent gears. Gear trains theory of machines engineering reference with. Epicyclic gear train solution techniques with application. The epicyclic gear first analysed here have the following components.
May 07, 2009 sumtorques with respect to input sum of intertias with respect to input and gear ratios x angular acceleration of input shaft the attempt at a solution now my problem is that there are no moments of inertia given for the gears in the system. Problems on trains questions answers mcq quantitative. Apr 04, 20 simple gear train when there is only one gear on each shaft, as shown in fig. Gear teeth are designed to ensure the pitch circles of. The rectangles contain the active outputs for that state. The paper illustrates the application of a systematic technique for thededuction of dynamic equations of epicyclic gear trains. May 17, 2017 in this video i explain about epicyclic gear train and how can we get different different speed ratio by one gear train. Here is a gearset with a stationary ring gear and three planet gears on a rotating carrier. Two inputs are needed to obtain a predictable output. These techniques have been applied to the problem of using an epicyclic gear train as a power coupling in a tandem bicycle.
All 34 types can be derived from one general form of the simple planetary gear train. Thediscussed examples illustrate how the presented approach can be extendedfor computing the equivalent inertia. Internal ringgear, three planets on spiderarm and the sun gear as semipictorial fig. In case there is a third gear there will be 3 trains and then 3 equations. A train is 100 meter long and is running at the speed of 30 km per hour. We use the method introduced in epicyclic ratio calculation for determining the final gear ratio of an epicyclic gear train. An epicyclic gear train also known as planetary gear consists of two gears mounted so that the centre of one gear revolves around the centre of the other. Ordinary gear trains have axes, relative to the frame, for all gears comprising the train. This video explains how to calculate gear ratios for compound gear trains and gearboxes.
A fixedring epicyclic gear train is required to have an overall ratio of 5. 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. When the distance between the two shafts is small, the two gears 1 and 2 are made to mesh with each other to transmit motion from one shaft to the other, as shown in fig. May 20, 2015 calculating the input power required for a drive gear in a train. A gear train is a mechanical system formed by mounting gears on a frame so the teeth of the gears engage. What is the relationship of the input shaft compared to the output shaft. Following are the different types of gear trains, depending upon the arrangement of wheels. In this gear system, the yellow gear the sun engages all three red gears the planets simultaneously. 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. Thus a gear train is a set or system of gears arranged to transfer rotational torque from one part of a mechanical system to another. It may be regarded as a set of four rigid bodies because. The owner would like your company to manufacture a shop display that is eye catching for passersby.
Problems on trains aptitude questions and answers are available on this web page. Please start with the tutorial for shaft calculation to see how to introduce geometry and supports for single shafts. Oct 17, 2017 more teething problems on gwrs brand new intercity express train this article is more than 2 years old rock fall causes delays and cancellations on trains second day after first outing. Sumtorques with respect to input sum of intertias with respect to input and gear ratios x angular acceleration of input shaft the attempt at a solution now my problem is that there are no moments of inertia given for the gears in the system. Gear train is any combination of gear wheels by which motion is transmitted from one shaft to another shaft. Dynamic analysis of epicyclic gear trains by means of. Define gear train and explain different types of gear train 25. The wheels e and f rotate on a pin fixed to the arm g. Epicyclic gearset gears 6 an epicyclic gear set has some gear or gears whose center revolves about some point. The stoeckicht planetary gear train used had both a floating sun and ring gear to. Compound gear train problem why is it so hard physics forums. More teething problems on gwrs brand new intercity express train this article is more than 2 years old rock fall causes delays and cancellations on trains second day after first outing. Reverted gear train when the axes of the first gear i. A twostage planetary gear stage is defined using the program.
1055 1619 932 631 1167 1272 1269 1189 955 1021 64 1244 380 1585 444 191 1468 155 292 226 995 403 1356 439 995 92 1406 365 1064 854