In this case, the fundamental formula for the planetary gear train yields. Given i have the solid works file,the pressure angle, and the gear ratios, i can easily calculate the distances, teeth numbers, etc. A gear train is a combination of gears used to transmit motion from one shaft to another. The planetary gear set, also known as the epicyclic gear train, is one of the most important and interesting inventions in engineering. In a compound epicyclic gear train as shown pdfinancialcorp com in the figure, has gears. Gears can be animated with various speed to demonstrate working mechanism.
Centrifugal force calculations of rotating body when gear rotates about any axis other than one at its center of mass. Designing compound epicyclic gear trains for maximum speed at high velocity ratios, machine design, april 4, 1957. Design, load analysis and optimization of compound epicyclic. Also different methods like tabulation and formula methods are discussed which are used to solve the questions based on planetary gear train.
The pinion is free to rotate on a pin fixed to the lever arm. A thorough understanding of the sometimes difficult material is facilitated through the use of both schematic and symbolic diagrams. For example, if the sun gear has 20 teeth and the ring gear has 60, the planetary gear has 80 teeth. The planet and sun gears mesh so that their pitch circles roll without slip.
In recent years the estimation of gearbox power loss is attracting more interest especially in the wind turbine and automotive gearbox industry but also in industrial gearboxes where heat dissipation is a consideration as well. Planetary gear systems have very smalllarge train ratios and are very compact. 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. The gear train consists of five external gears and 4 internal annulus gears, including sun and planet gears forming an epicyclic gear train. Figure 1 the basic components of a planetary gearhead. This system is reminiscent of the planets orbits around the sun, thus giving the gear system its name. One of the planetary gearsets from our transmission has a ring gear with 72 teeth and a sun gear with 30 teeth. The gear train maybe for spur gear, helical gear and spiral gear. This does not generate planetary gears, and im also unclear as to how design a planetary gear with a 2. A network theory for variable epicyclic gear trains technische.
Equation and calculators to determine ratios of planetary or epicyclic gear assemblies. The sun gear, planet gear, annulus are design in solidwokrs software. They are great speed variation mechanisms, and are often. Mar 30, 2016 epicyclic gear train an epicyclic gear train,the axes of the shafts, over which the gears are mounted, may move relative to a fixed axis. On completion of this short tutorial you should be able to do the following.
A twostage planetary gear stage is defined using the program. This forms a planetary gear train with a fixed carrier train ratio r. The earliest known reference to gear trains is in a treatise by hero of alexandria c. 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. Recent articles in gear solutions have discussed epicyclic gearing, but often in the context of experienced engineers. Application of the element relations to a complete train is carried out as shown in the example which follows. Sort by date 1 design unit evaluating new software from smt januaryfebruary 2007. What is the advantage and disadvantage of a epicyclic gear. Calculations show that a set of 20 gears will generate, for example, 380 sets of 2gear arrangements, 29,070 sets of 4gear and 775,200 sets of 6gear.
The sun gear is located at the center of the gear train solar system. Structure and analysis of planetary gear trains prof. Stress analysis and mass optimization of epicyclic gearbox housing. To define a train, consider that it has always the arm r, a gear of the planet and a main gear. This block models a gear train with sun, planet, and ring gears. 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. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear.
Note that a zero velocity input to the arm merely makes a conventional train out of the epicyclic train as shown in figure 932a. 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. How to i design a planetary gear with a gear ratio of 2. 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.
Epicyclic gear trains have two degrees of freedom and, in order to determine their motion, two inputs must be defined. In this simple example of an epicyclic train, the only gear left to take an output from. Types of gear train and velocity ratio calculation techminy. How to get the most realistic efficiency calculation for gearboxes. Understanding epicyclic gear train construction and working by akash gaikwad patil this video is about epicyclic gear train an epicyclic gear train also known as planetary.
The gear b meshes with gear a and has its axis on the arm at o2, about which the gear b can rotate. This method is extremely procedural, which is appropriate since use of intuition is often quite futile when applied to complex gear trains. Publishers pdf, also known as version of record includes final page, issue and volume. D rotation of driver per revolution of follower or the driven gear or pulley.
The second sun gear serves the same purpose as the annular gear of a simple planetary gear train, but clearly does not have the internal gear mate that is typical of an annular gear. The compound planetary gear train taken from the elecon engineering shown in figure 2. Epicyclic gear calculations pdf with four core components, calculating the gear ratio of planetary gear systems, also known as epicyclic gear systems, may seem daunting. Figures 1 present differentialplanetary arrangements with compound planet gear train. In addition it let you compose full gear layouts with connetcted gears to design multiple gears system with control of the inputoutput ratio and rotation speed. Its also possible to use the annulus gear or the planet carrier as drive. Design of machinery an introduction to the synthesis and. By using epicyclic gear, different torque speed ratio can be obtained. Planetary gear system could be used to secure higher gear ratio in compact space. It is stated that the simple planetary gear train consisting. The gears must rotate maintaining a fixed ratio of angular velocities relative to the carrier body. This planetary gear train consists of a sun gear yellow, planet gears blue supported by the. Calculate the input and outputs speeds and torques of gear. We present here a simple, methodical procedure for determining the final gear ratio of an epicyclic gear train.
Each of these three components can be the input, the output or can be held stationary. Mullers discovery of their perfect analogy to the simple epicyclic drive trains. The term power transmission is defined as the move ment of. Pdf design, load analysis and optimization of compound. Epicyclic planetary gear system 3d cad model library. Design and analysis of an epicyclic gearbox for an electric.
The sign is negative for exterior gears and positive for interior gears. The following two methods may be used for finding out the velocity ratio of an epicyclic gear train. In case there is a third gear there will be 3 trains and then 3 equations. 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. Ansys workbench and reduce the mass of the epicyclic gear train housing by using matlab optimization tool box. Thus the conventional gear train is simply a special case of the more complex epicyclic train, in which its arm is held stationary. It require small area during the power transmission and to obtain large speed reduction. It can be seen that the gear paircarrier system has two.
Understanding, selecting and applying planetary gearheads. Thus, they differ from an ordinary train by having a. Calculating gear ratios within a planetary gear set youtube. This video introduces the concept of epicyclic gear trains, how dramatically they differ and their degree of freedom using animation. Thus, it is not difficult to get the velocity ratio of the gear train in figure 76b. Epicyclic gearset gears 6 an epicyclic gear set has some gear or gears whose center revolves about some point.
The background history of these epicyclic gear trains is outlined, general. Dec, 2010 kinematics with microstation ch06o epicyclic gear trains. In the past ive had luck using this site to create an illustrator file that i can extrude in rhino. Examine your lathe and see if it has a geartrain setup similar to that shown above and in the geartrain. Jul 06, 2019 epicyclic gear calculations pdf with four core components, calculating the gear ratio of planetary gear systems, also known as epicyclic gear systems, may seem daunting. On the ring gear blue the torque arm is attached so its speed is zero. Epicyclic drive trains analysis synthesis and applications. The next steps depend on the state of the planetary gears connected to the carrier, although all use the same formula. Understanding, selecting and applying planetary gearheads howard horn, product manager. Zoltan levai received 9 february 1968 abstract both compound and internal or external planet gears are considered as well as the paired planet gears.
Stress analysis and mass optimization of epicyclic gearbox. Gear ratio equations and calculators of planetary or epicyclic gear assemblies gear ratio equations and. A bearer associates the focuses of the two gears and turns to convey one gear, called the planet gear or planet pinion, around the other, called the sun gear or sun wheel. Please start with the tutorial for shaft calculation to see how to introduce geometry and supports for single shafts. Pdf epicyclic gear train dynamics including mesh efficiency. 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 gear wheel transmitted motion between one shaft to another shaft, so the multiple set of gear transmit motion from single main gear to various revolving parts is known as gear train. Planetary gears are common in transmission systems, where they provide high gear ratios in compact geometries. Planetary epicyclic gear ratios equations and calculators. The tool investigated is from atlas copco st series and consists of three main parts. Calculate gear ratio by dividing the number of teeth on the driven gear by the number of teeth on the driving gear. Choosing which piece plays which role determines the gear ratio for the gearset. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves around the center of the other.
Calculating load on planetary gear from driving torque. We use the method introduced in epicyclic ratio calculation for determining the final gear ratio of an epicyclic gear train. A spur gear differential is constructed from two identical coaxial epicyclic gear trains assembled with a single carrier such that their planet gears are engaged. Everything you need to print a complete, printable and full functional epicyclic gearing train. A fixedring epicyclic gear train is required to have an overall ratio of 5. But in case of epicyclic gear trains, the axes of the shafts on which the gears are mounted may move relative to a. 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. 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 carrier connected to a drive shaft holds the planet gears. These sets of lineal equations underlie the variator rletworj, theory in. 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. Pdf the mechanical efficiency of epicyclic gear trains. In this simple example of an epicyclic train, the only gear left to take an output. How to calculate the gear ratio in a planetary gear set where one member is stationary. Gear trains are widely used in all kinds of mechanisms and machines, from can. 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.
Apart from this, some objective questions have also been discussed in detail which were asked in previous years in engineering services examination. Describe three types of epicyclic gear boxes solve gear box ratios. Epicyclic gearing arrangements are comprised of four different elements that produce a wide range of speed ratios in a compact layout. Epicyclic definition of epicyclic by the free dictionary. The planetary gears may also mesh with an internal ring gear. Is there a general equation i can use without knowing the power and the rpm. Advantages of planetary gear system planetary gear system has lots of advantage as compared to traditional gearboxes 1. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes. An approach to powerflow and static force analysis in. These drives receive an unusually clear treatment because at dr. An epicyclic gear train otherwise called planetary gear comprises of two gears mounted with the goal that the focal point of one gear spins around the focal point of the other.
Calculating the load on planetary gear from driving torque. I also know the initial driving torque of the sun gear. As more and more of these engineers reach retirement age younger engineers must pick up where they left off, and for many epicyclic gearing is an area where they lack experience. The arrangements of planetary gear train are shown in figure 1. Ports c, r, and s represent the shafts connected to the planet gear carrier, ring gear, and sun gear. More complex epicyclic trains may be analysed in a similar manner, but the technique is not of much assistance when the problem is one of gear train design the interested designer is referred to the bibliography. The mechanical efficiency of epicyclic gear trains. Epicyclic train dynamometer which measures power while it is being transmitted from driving to the driven shaft. This leads to different gear ratios and output rotation.
Following are the different types of gear trains, depending upon the arrangement of wheels. Introduction to mechanisms carnegie mellon school of. How to get the most realistic efficiency calculation for. When two gears meet their pitch circles are tangent to each other. Gear train with sun, planet, and ring gears matlab. The book is profusely illustrated and analyzes many applications. In discussing the spur gear differential, the use of the term annular gear is a convenient way to distinguish the sun gears of the two epicyclic gear trains. Calculate gear ratio by dividing the number of teeth. Planetary gearheads are used on high precision motion control applications that.
This example shows an epicyclic gear drive with overall ratio of 256. The lever is pivoted about common axis of the driving and driven shaft. Solid mechanics tutorial gear systems this work covers elements of the syllabus for the edexcel module 21722p hncd mechanical principles outcome 3. So, my question is, utilizing the solid works file and the driving sun gear torque how do i calculate the load on the contact point for each of the gears. Velocity ratios and gear trains for the gear train shown below, determine the train value, output speed, output direction, output torque, and output power. Gear generator is a tool for creating involute spur gears and download them in svg format. Calculation of a planetary gear train this tutorial shows the usage of mesys shaft calculation with shaft systems. Velocity ratio of a compound epicyclic gear objective to study the velocity ratios of an epicyclic gear by locking. This lesson tells about basics of planetary 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. To demonstrate the analysis, a new motorgenerator integrated hybrid transmission design is used to show how the torque acting on each link of an epicyclic gear train egt can be systematically solved in terms of input torques andor controlled output torque. Tooth load and torque calculations in epicyclic gear trains. Best epicyclic gear train in mechanical engineering. Mar 20, 2020 an epicyclic gear, also referred to as a planetary gear, is a gearing system in which gears known as planetary gears revolve around one central gear referred to as the sun gear.
Here is a gearset with a stationary ring gear and three planet gears on a rotating carrier. Epicyclic gear trains include a sun gear, a planet carrier, and one or more planetary gears. Graphtheoretic modelling of epicyclic gear systems. Im working on a solution to this problem and i would like some advice and help. In screw technology, planetary gears are usually driven on the central gear yellow. Please consider this design as a basis to be customised to your own application. 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.
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