Planetary gear ratio calculation pdf

In a conventional manual transmission gearbox application there are two 2 gears involved driven and drive for any given gear ratio. Planetary gear system is use in varies applications such as, clocks, lunar calendar, car mirror, toys, gearhead motor, turbine engine and many more. Intuitive method how to calculate derive gear ratio formulas equations for planetary epicyclic gear. 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. Tooth contact analysis was performed to calculate the. Schlecht, calculation of load distribution in planetary gears for an effective gear design process, agma, oct.

Additionally, there is a diversity of planetary gears for. The gearbox is made from hardened steel and has a gear ratio of 35 times in order to. Zoltan levai received 9 february 1968 abstract both compound and internal or external planet gears are considered as well as the paired planet gears. New design and improvement of planetary gear trains faydor l.

In the past ive had luck using this site to create an illustrator file that i can extrude in rhino. Feb 20, 2015 how to calculate the gear ratio in a planetary gear set where one member is stationary. That is to say, the number of teeth in the ring gear is equal to the number of teeth in the middle sun gear plus twice the number of teeth in the planet gears. Gear generator is a tool for creating involute spur gears and download them in dxf or svg format. An electric motor operates the planetary gear train via a belt multiplying the rotational speed of the planet carrier up to a maximum of 6000 rpm, i.

How to derive the formula for the planetary mechanism. The first constraint for a planetary gear to work out is that all teeth have the same pitch, or tooth spacing. 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. Internet searches for how to proved fruitless and dare i say information is being withheld, so this programmer set out to demystify the methods for calculating the widely used equations of. Elec tric mo to r gt1 gt2 scre w driv er sh af t sw itc h mo t o r sha f t t. On completion of this short tutorial you should be able to do the following. Nov 08, 2012 the overall demultiplication of multi stage planetary gear units is calculated by multiplying the ratios of the single stages. How to i design a planetary gear with a gear ratio of 2. Design, modelling and analysis of a 3 stage epicyclic planetary reduction gear unit of a flight vehicle k akhila1 and m amarnath reddy2 corresponding author. Planetary gear trains are one of the main subdivisions of the simple epicyclic gear train family. 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.

Drivetrains purpose and function the purpose of a vehicle drivetrain is to. When the larger gear makes one full revolution, the smaller gear has to spin faster to keep up. Jan 09, 2018 the gear ratio formula for two meshing gears is simple and intuitive, while the gear ratio formula for the planetary mechanism is not. Calculation of a planetary gear train this tutorial shows the usage of mesys shaft calculation with shaft systems. Engagement between internal gear and pinion external gear centre distance ca for the internal. Calculate gear ratio by dividing the number of teeth on the driven gear by the number of teeth on the driving gear. The comparison of planetary gear system over helical gears systems is done on the basis of volume, weight and torque density keywords. A coil of wire is rotated in a magnetic field to create a flow of electrons. Two forms of planetary gears of the bevel type are shown in figures 23 and 24. Also the case study to determine the reduction ratio of two stage gear box is discussed. Reliability our planetary gears accomplish reliable performance in their numerous applications.

Equation and calculators to determine ratios of planetary or epicyclic gear assemblies. A convenient approach to determine the various speed ratios available in a planetary gear train. From a loadcapacity point of view, the most suitable gearhead ratio has the highest torque density for the most compact and costeffective package. Bear in mind the difference between the standard reduction ratio fo framenumbers under 315 and over 355. A carrier connected to a drive shaft holds the planet gears. The overall demultiplication of multi stage planetary gear units is calculated by multiplying the ratios of the single stages. 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. In general, a planetary stage is designed for gear ratio up to seven and a parallel stage usually up to five. It is stated that the simple planetary gear train consisting. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves.

Calculation of the equivalent working torque me knm when loads are intermittent see histogram 1, we must. The number of teeth of the planets has no effect on the ratio. Planetary epicyclic gear ratios equations and calculators. Pdf in this report equations for the minimum gear sizes necessary to drive a. Planet carrier types of mechanism fixed member input output formula of gear ratio ratio. To determine a gear ratio, divide the driven gear by the driving gear. Calculate the number if teeth required in the ring gear for the ratio 5. How to derive the formula for the planetary mechanism gear ratio duration. In order to achieve the above objective, methodology of design used is explained in next point. Calculation of number teeth of sun, planets and ring gear. Recent articles in gear solutions have discussed epicyclic gearing, but often in the context of experienced engineers.

Relationship ii can be verified by using the following. Planetary gears are known for their high efficiency. A simple planetary with a single carrier, sun gear, and ring gear can be connected. Planetary gear ratio calculations this article also available in spanish. How to derive and calculate epicyclic gear ratio equations. Relations between size and gear ratio in spur and planetary gear trains. Add them together to calculate the number of planetary gear teeth. Each of these three components can be the input, the output or can be held stationary. Pintz cleveland state university cleveland, ohio prepared for lewisresearchcenter under grant nag3o186 nlsa nationalaeronautics and spaceadministration sclentlllcand technical informationbranch 1984.

One of the planetary gearsets from our transmission has a ring gear with 72 teeth and a sun gear with 30 teeth. This does not generate planetary gears, and im also unclear as to how design a planetary gear with a 2. Structure and analysis of planetary gear trains prof. The answer lies in the mechanism called a planetary gear mechanism. According to mueller, two fundamental planetary gear trains are kinematically equivalent if one gear ratio of a transmission is equal to.

A compound configuration for planetary gear train is selected and an. In our example, dividing the 30 teeth of the driven gear by the 20 teeth of the drive gear gets us 3020 1. Research laboratory new design and improvement of planetary. Following this step, the gear ratio is calculated by dividing the number of driven teeth by the number of driving teeth there are three combinations possible, depending on whether the carrier is moving, being moved or standing still. Wind energy math calculations gear ratios you may have learned about the way an electric generator works.

Then, how does a transmission change the reduction ratio. A gear ratio is the relationship between the number of teeth on two or more gears that are meshed. The gear ratio formula for two meshing gears is simple and intuitive, while the gear ratio formula for the planetary mechanism is not. In the picture above, meshing is the sun gear a the planetary gear b the planetary gear c coupled with the gear b the sun gear d concentric to but not coupled with the gear b and the gear a is fixed, while the arm e rotates.

These gears can only offer two 2 variations between the input shaft and output shaft, forward or reverse but the ratio remains the same. How to calculate the gear ratio in a planetary gear set where one. The comparison of planetary gear system over helical gears systems is. For the predefined gear ratios, one negative ratio drive and two structurally different positive ratio drives will be designed and compared fig. This is the basis of how a wind turbine makes electricity. A question that i often get is how to work out planetary gears using the gear template generator working out the tooth counts for planetary gears is actually not that complicated, so i initially neglected to mention how to do it. The outermost gear, the ring gear, meshes with each of the planet gears. Owing to the high manufacturing quality of our gearbox series we offer you an excellent priceperformance ratio. The next steps depend on the state of the planetary gears connected to the carrier, although all use the same formula.

Design and optimization of planetary gears considering all relevant influences tobias schulze gear design process lightweight construction and consideration of available resources result in gearbox designs with high load capacity and power density. Atlas copcos previous knowledge about power losses in planetary gears. Basic gear axis for planetary gear train mechanism 2kh a types of planetary b types of solar c types of star aa. Choosing which piece plays which role determines the gear ratio for the gearset. Lightweight design for planetary gear transmissions. Compound gears are simply a chain of simple gear trains with the input of the second being the output of the first. The noload power losses produced by the planetary gear train are determined from direct torque measurements by.

Gear train with sun, planet, and ring gears matlab. A wind turbine gearbox typically contains one lowspeed planetary stage with two parallel stages or two planetary stages with one highspeed parallel stage. Understanding, selecting and applying planetary gearheads. At the same time, expectations for gear reliability are high. This text will not deal with the stress analysis aspects of gear design. Sharing is caring 1 1sharegear ratio is the ratio of output and input number of teeth on a shaft.

For example, if the sun gear has 20 teeth and the ring gear has 60, the planetary gear has 80 teeth. You can obtain large speed ratio using small machine. Abstract it has been said that deriving the formulas for the ratios between the various gears of an epicyclic planetary gear system is nonintuitive and taxes the human intellect to say the least. The gear ratio of an epicyclic gearing system is somewhat nonintuitive. For the predefined gear ratios, one negativeratio drive and two structurally different positiveratio drives will be designed and compared fig. Calculating gear ratios within a planetary gear set youtube.

Planetary gears, gear train, is 4460, torque density. The gear attached to the motor shaft is considered the first gear, or the drive gear, and the other gear, whose teeth are meshed with the drive gear, is considered the second gear, or driven gear. Due to technology improvement, the mechanisms are working with less and less losses, but their constructions are becoming more complex. Reduction ratios not listed in chart 1 require special design.

This essay is dedicated to the planetary gear sets. How to derive and calculate epicyclic gear ratio equations in. A question that i often get is how to work out planetary gears using the gear template generator. Planetary gears are common in transmission systems, where they provide high gear ratios in compact geometries. D rotation of driver per revolution of follower or the driven gear or pulley. 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. Relations between size and gear ratio in spur and planetary gear trains 635 2 equivalent load the load in a mechatronic application is usually a combination of inertial and friction. Planetary gears considering all relevant influences tobias schulze gear design process lightweight construction and consideration of available resources result in gearbox designs with high load capacity and power density. Ports c, r, and s represent the shafts connected to the planet gear carrier, ring gear, and sun gear.

Basic gear terminology and calculation lets learn the basics of basic gear technology. How to calculate the gear ratio in a planetary gear set where one member is stationary. Their number of teeth depends on the demultiplication of the gearbox. The next chapter explains the matlab calculation program based on the. So when you ride your bicycle, the gear in front might have 48 teeth, while the gear in back has 16 teeth. In this tutorial, we will show you an original and easyto. Select the nearest reduction ratio from among the ratios of the standard reduction ratio chart see chart 1. Solid mechanics tutorial gear systems this work covers elements of the syllabus for the edexcel module 21722p hncd mechanical principles outcome 3.

Also, locking any two of the three components together will lock up the whole device at a 1. Planetary gear boxes chapter 10 7 technical information table 3 at the end of this section includes some examples of load classifications. Pdf relations between size and gear ratio in spur and planetary. Let us compare a planetary gear train with a conventional one, with fixed gear axes, designed for the same gear ratio of angular velocities of the input and output mechanism links. Working out the tooth counts for planetary gears is actually not that complicated, so i initially neglected to mention how to do it.

The gsf090 planetary gear, with a gear ratio of i10, is used as a machine axis. Relations between size and gear ratio researchgate. Multistage gears are required to obtain the desired ratio. Gear size, pressure angle, number of teethwe introduce the basic terminology, measurement, and relational expressions necessary to understand basic gear technology. Driver planetary gear character istics this is a c o mp li c a t e d m e c h a n ism to solve.

The epicyclic gear train family in general has a central sun gear which meshes with and is surrounded by planet gears. The tool investigated is from atlas copco st series and consists of three main parts. Types of gear train and velocity ratio calculation gear train mean. Types of gear train and velocity ratio calculation techminy. Our high quality standards apply to all our planetary gearbox series. The planets are merely seen as a bridge between the sun gear and annulus gear. The power transfer is an irreplaceable part of every industry. A simple equation is used to find the ratio of your gearing system number of teeth on the driven gear number of teeth on the drivergear. In this article we will discuss gear ratio calculations for various gear train. A planetary gear mechanism is a gear mechanism consisting of 4 components, namely, sun gear a, several planet gears b, internal gear c and carrier d that connects planet gears as seen in the graph below. A twostage planetary gear stage is defined using the program. Intro planetary gears also refer as epicyclic gearing consisting three elements sun. The three main types of simple epicyclic gears are the planetary, the star, and the solar.

Please start with the tutorial for shaft calculation to see how to introduce geometry and supports for single shafts. A complete gear train design will necessarily involve considerations of strength of materials and the complicated stress states to which gear teeth are subjected. Design of machinery an introduction to the synthesis and. Litvin, alfonso fuentes, daniele vecchiato, and ignacio gonzalezperez university of illinois at chicago chicago, illinois 606077022 summary the development of new types of planetary and planetary face gear drives is proposed. Being your reliable partner and supplier is our constant driving force.