Gear trains of the type shown in figures 1, 3, 4 and 5 are called epicyclic gear trains or planetary gear trains. A network theory for variable epicyclic gear trains citation for published version apa. Having more teeth in mesh, not shifting the load so abruptly, also reduces the noise level. Planetary or epicyclic gear train epicyclic gear train. Regulations, doubts and concerns may thwart railway mergers. The total mechanical loss is then given as the sum of losses from all gear meshes and bearings. This accounts for epicyclic gear trains being more quiet than parallel shaft gear trains. The planet and sun gears mesh so that their pitch circles roll without slip. If the arm is the input and the planet is the output, the overall gear ratio is 31 3. Several overall gear ratios can be provided by selecting various first stage ratios. Generally, singlestage epicyclic gear trains are more efficient than equivalent parallel shaft gear trains. It require small area during the power transmission and to obtain large speed reduction.
Canadian pacific has tried three times to acquire norfolk southern. Simple gear trains schematic of simple gear train a simple gear train is a number of simple gear pairs in series. An epicyclic gear train is shown schematically in the adjacent figure. Problem no 2 on epicyclic gear train gear trains kinematics of machinery theory of machines duration. Design, load analysis and optimization of compound epicyclic gear trains syed ibrahim dilawer1, md.
In epicyclic gear trains, the axes of shafts on which the gears are mounted may move relative to a fixed axis. One of the most important considerations for an epicyclic gear is to assure uniform load distribution among the planets. Software gto provides the required results in a very short time. The use of theproposed method is particularly amenable in conjuction with proceduresfor the computerized enumeration of geared kinematic chains. They are used to achieve high gear ratio within limited space. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear. In this lesson, we will study about epicyclic gear trains, planetary gear trains, easy method to solve numerals on epicyclic gear train and holding torque of gears. 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.
Please start with the tutorial for shaft calculation to see how to introduce geometry and supports for single shafts. The epicyclic gear trains are useful for transmitting high velocity. Ordinary gear trains have axes, relative to the frame, for all gears comprising the train. Enumeration of epicyclictype automatic transmission gear trains. A basic example is a singlestage gear unit withthree fixedplanets and a rotating carrier know as a star epicyclic gear. 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. Jul 11, 2015 applications the epicyclic gear trains are useful for transmitting high velocity ratios with gears of moderate size in a comparatively lesser space. More useful, however, are the epicyclic trains referred to as the simple and complex planetary gear trains, where a second sun gear is used. Gear ratio product of driven teethproduct of driving teeth gear ratio 100 x 100 x 100 20 x 40 x 10 125 alternatively we can say there are three simple gear trains and work ot the ratio for each.
Epicyclic gearing also called as planetary gearing. Another class of gear train has wide application, the epicyclic or planetary train. It contain epicyclic gear arrangement, fluid coupling and torque converter. This type of transmission are used by skoda,toyota, lexus, etc epicyclic gearing planetry gearing. Two forms of planetary gears of the bevel type are shown in figures 23 and 24. 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. Usually, following two types of lubrication mechanisms are commonly used for gear lubrication. A substantial amount of literature is available for planar linkages. A gear train is a combination of gears used to transmit motion from one shaft to another.
Epicyclic gearing requires a stepbystep process to make it work, and some of the steps are not necessarily intuitive. The ic was by far the dominate player in the chino market. Most automatic transmissions employ some kind of epicyclic gear mechanisms to achieve the above purpose. Maakt het mogelijk om pdfbestanden samen te voegen met een simpele drag anddrop interface. 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. Thediscussed examples illustrate how the presented approach can be extendedfor computing the equivalent inertia of an. The stationary gear sun gear or ring gear can be referred to as the central gear. The gear train maybe for spur gear, helical gear and spiral gear. In some cases, such as the automotive differential, one input is provided the. Solid mechanics tutorial gear systems this work covers elements of the syllabus for the edexcel module 21722p hncd mechanical principles outcome 3.
This is made possible in a 3 or more planet arrangement. Types of gear trains asimple gear train bcompound gear. These gear trains can be realized in any of the twelve arrangements set forth in 3. Gears are compact, positiveengagement, power transmission elements capable of changing the amount. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can rotate. In 1967, a combination of seaboard air line and atlantic coast line produced seaboard coast line. 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.
Tooth load and torque calculations in 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. An efficient method of achieving high reduction ratios in minimum space is the use of planetary gearing. Calculation of a planetary gear train this tutorial shows the usage of mesys shaft calculation with shaft systems. All 34 types can be derived from one general form of the simple planetary gear train. Motor angular displacement and load angular displacement and their derivatives are related by the gear ratio n. The first step in the design process of such a mechanism involves finding a configuration that provides a set of desired speed ratios, and meets other dynamic and kinematic requirements. 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. For a more involved epicyclic gear train example, please refer to the epicyclic gear train example section. With the rotation of each element of the gear train in hand, the overall gear ratio becomes easy. L where a gear a and the arm c have a common axis at o 1 about which they can rotate. Simple gear trains, compound gear trains for large speed reduction, epicyclic gear trains algebraic and tabular methods of finding velocity ratio of epicyclic gear trains. Yi zhang with susan finger stephannie behrens table of contents.
Following are the different types of gear trains, depending upon the arrangement of wheels. In this example, gear 1 and gear 3 are on the same axis. 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. Reverted gear trains are a type of compound gear trains in which input and output shafts are on the same axis.
A network theory for variable epicyclic gear trains. Types of gear train and velocity ratio calculation techminy. What is the advantage and disadvantage of a epicyclic gear. Rvaf en 004 high precision cycloidal gear manufacturer. Lightweight design for planetary gear transmissions. Planetary epicyclic gear ratios equations and calculators. Introduction to epicyclic gear train working and advantages. Epicyclic gear train nptel pdf in the first three types of gear trains, the axes of the shafts over which the gears are mounted are. Epicyclic gear trains have broad applications in automobile, aerospace, mill, and automation industries, such as. Gear trains for web faculty of engineering, university of.
In this planetary gears sets are placed in series to provide transmission. Helical gear the teeth on helical gears are cut at an angle to the face of the gear this gradual engagement makes helical gears operate much more smoothly and quietly than spur gears one interesting thing about helical gears is that if the angles of the gear teeth are correct, they can be mounted on perpendicular shafts, adjusting the rotation angle by 90 degrees. On completion of this short tutorial you should be able to do the following. The angular speed of the planet carrier can be found since we know. Epicyclic gear train apparatus manufacturer supplier india. Pdf design, load analysis and optimization of compound. The ring gear 5 is fixed and the gear 2 is rotating at 60 rpn ccw ccwcounterclockwise and cw clockwise. Reverted gear train pdf following are the different types of gear trains, depending upon the arrangement of wheels. Two inputs are needed to obtain a predictable output. Advantages of planetary gear system planetary gear system has lots of advantage as compared to traditional gearboxes 1.
Planetary gear trains are one of the main subdivisions of the simple epicyclic gear train family. The epicyclic gear trains may be simple or compound. Trains magazine offers railroad news, railroad industry insight, commentary on todays freight railroads, passenger service amtrak, locomotive technology, railroad preservation and history, railfan opportunities tourist railroads, fan trips, and great railroad photography. Epicyclic gear train solution techniques with application to. Plane t a r y gear tra i n s consis t o f the follo w i n g. It is established which variants of twospeed planetary gear trains are possible to combine by means of corresponding clutches in order to.
All the components are modelled in catia to check the assembly and the. In case there is a third gear there will be 3 trains and then 3 equations. Power flow and efficiency analysis of epicyclic gear. The volume of the gear train with spur gears is reduced by 22. 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. For the predefined gear ratios, one negativeratio drive and two structurally different positiveratio drives will be designed and compared fig. Riveted gear train gear ratio is calculated similar to compound gear train. 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. Freudenstein i in 1955, gave an appropriate but a numerical method for dimensional synthesis of a four bar linkage. A twostage planetary gear stage is defined using the program. The planet gear in figure 23 rotates about a fixed bevel gear at the center of which is the driven shaft. Epicyclic gear trains are generally used for automatic transmission, overdrives, and final drives.
To define a train, consider that it has always the arm r, a gear of the planet and a main gear. In these gear trains, one or more gears are carried on a rotating planet carrier rather than on a shaft that rotates on a fixed axis. The gear b meshes with gear a and has its axis on the arm at o2, about which the gear b can rotate. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which. Epicyclic gear train nptel pdf merge this planetary gear train consists of a sun gear yellow, planet gears blue supported by the. Design of machinery an introduction to the synthesis and. 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.
A pgt has been represented by its functional schematic, structural and kinematic graph. Epicyclic gear trains are known to provide high power density and have become the gear train of choice for the main power flow in virtually all rotorcraft designs. Planetary gears, which can supply a lot of speed reduction and torque in a small package, have operating characteristics beyond those of fixedaxis gear trains. In epicyclic gear train, different types of gear are used like spur gear, helical gear, bevel gear and many more. Gear train is any combination of gear wheels by which motion is transmitted from one shaft to another shaft. Epicyclic gear trains cambridgemit multidisciplinary. Dynamic analysis of epicyclic gear trains by means of. The planetary gear set, also known as the epicyclic gear train, is one of the most important and interesting inventions in engineering. 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. Jul 18, 2017 a gear train is a combination of gears used to transmit motion from one shaft to another. 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. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves around the center of the other. Introduction to epicyclic gear train working and advantages and disadvantages of the epicyclic gear train.
Dec 21, 2015 regulations, doubts and concerns may thwart railway mergers a canadian pacific freight train near the rocky mountains. When pinion is the driver, it results in step down drive in which nptl output speed. An input gear engages with and rotates spur gears that are coupled to crankshafts. The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc. In this paper, graph theory is used for the study of epicyclic gear trains or planet gear trains e. Design, load analysis and optimization of compound epicyclic. Gear trains are widely used in all kinds of mechanisms and machines, from can openers to aircraft carriers.
The earliest known reference to gear trains is in a treatise by hero of alexandria c. The sun gear2 on the input shaft is a 20 teeth external gear. Predetermining internal power flows of an epicyclic gear train is critical to a successful design, because the internal power flows may yield significant power losses at gear meshes and fail the concept. The planet gear are mounted on a moveable arm carrier. The reciprocal of the speed ratio or velocity is known as train value. Design, load analysis and optimization of compound epicyclic gear trains article pdf available october 20 with 1,104 reads how we measure reads. With involute profile of gears, only one contact position experiences pure rolling.
Example 6 figure shows a compound epicyclic gear train, gears s1 and s2 being rigidly attached to the shaft q. It is a gear system that consists of one or more outer gear planet gear rotating about a central sun gear. Previous years gate questions on gear trains 200820. The analysis of the gear train is relatively simple, but the result may be unexpected. A merger of two or more big railroads would increase the combined carriers commercial breadth and scope, and broaden the services it could offer. But in case of epicyclic gear trains, the axes of the shafts on which the gears are mounted may move relative to a. Pdf the mechanical efficiency of epicyclic gear trains. Advantages of an epicyclic gear artec machine systems. 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. Epicyclic gear trains also known as a planetary gear train are gear trains with relative motions of axes. Epicyclic gear train nptel pdf automatic transmission has not better fuel economy. Epicyclic gear train nptel pdf merge the total mechanical loss is then given as the sum of losses from all gear meshes and bearings. Types of gear train simple, compound, reverted, epicyclic.
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