So four design variables are considered namely module m, number of teeth on sun gear t1, number of teeth on planet gear t2 and face width of gear b. The sun and planet gear converted the vertical motion of a beam, driven by a steam engine, into circular motion using a planet, a cogwheel fixed at the end of the connecting rod connected to the beam of the engine. Pdf investigation of materials for shaft and sun gear of. A gear train is two or more gear working together by meshing their teeth and. Types of gear train and velocity ratio calculation techminy. The epicyclic gear train family in general has a central sun gear which meshes with and is surrounded by planet gears. The sun and planet gear is a method of converting reciprocating motion to rotary motion and was used in the first rotative beam engines it was invented by the scottish engineer william murdoch, an employee of boulton and watt, but was patented by james watt in october 1781. Zoltan levai received 9 february 1968 abstract both compound and internal or external planet gears are considered as well as the paired planet gears. Other uses for gears how gear ratios work howstuffworks. It is stated that the simple planetary gear train consisting.
In the toothed formation sun and planet gears are externally mesh and ring gear internally meshes. This gear has an inner hub c which is fixed to b and in mesh with the fixed ring gear r. In a planetary train at least one of the gears must revolve around another gear in the gear train. The two sun gears are centrally located and separated longitudinally along a common rotation axis. This arrangement uses a common sun gear shared by both planetary gear sets. A common use of a planetary gear set is in an automatic transmission where two 2 planetary gear sets are combined. Lightweight design for planetary gear transmissions.
Pdf epicyclic gear train dynamics including mesh efficiency. The smaller of these gears engages an inner planet gear set, which in turn engages an outer planet gear. You could rearrange things again, and this time hold the sun gear stationary, take the output from the planet carrier and hook the input up to the ring gear. 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. The selected materials had to meet strength requirements while being cost effective. Planetary gears are common in transmission systems, where they provide high gear ratios in compact geometries. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves. A planetary gear train is a little more complex than other types of gear trains. The combination of epicycle gear trains with a planet engaging both a sun gear and a ring gear is called a planetary gear. Calculation of number teeth of sun, planets and ring gear. One of the popular arrangements is called the simpson gear train. Simple compoundgear train n n n n t t t t r nn nn rr rr. Relative velocity of the sun planet gear mesh along loa. The outermost gear, the ring gear, meshes with each of the planet gears.
For the attached model, the relations are shown as example 1 in the bottom section of the excel file. Solid mechanics tutorial gear systems this work covers elements of the syllabus for the edexcel module 21722p hncd mechanical principles outcome 3. Gear trains theory of machines engineering reference with. Consequently, the dimensions of the sun gear would be onethird of the pinion of a parallel shaft geartrain designed to transmit an equivalent torque. Working out planetary gear turns ratios working out the gear ratio of a planetary gear train can be. Example for, sun and planet gear is a compound epicyclic gear train. The computeraided design cad files and all associated content posted to this website are created. For a planetary arrangement with three planets, each tooth engagement of the sun gear would have to carry one third of the total load. How epicyclic sun and planet gear box train works youtube. Planet gear for each planet gear, we can write nslr as follows. Gear 1 is called a sun gear, gear 2 is a planet, link h is an arm, or planet carrier. Sun gear is located at the centre that transmits torque to planet gears. What is the degree of freedom in epicyclic gear train.
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. Planetary or epicyclic gear train gear train mechanical. The grabcad library offers millions of free cad designs, cad files, and 3d models. Oct 18, 2015 a new nonlinear bendingtorsional coupled model for doublerow planetary gear set was proposed, and planets eccentricity error, static transmission error, and timevarying meshing stiffness were taken into consideration. The planets, spaced around the central axis of rotation, mesh with the sun as well as the fixed ring gear, so they. Such a gear configuration has useful applications, but the overall gear ratio is quite difficult to intuitively calculate. The tool investigated is from atlas copco st series and consists of three main parts. The nature of the train used depends upon the velocity ratio required and the. Each of these three components can be the input, the output or can be held stationary. The next steps depend on the state of the planetary gears connected to the carrier, although all use the same formula. The ravigneaux gear block represents a planetary gear train with dual sun and planet gear sets. The planetary gear set is the device that produces different gear ratios through the same set of. Introduction planetary gear systems normally consist of a centrally pivoted sun gear, a ring gear, and several planet gears found.
Planetary gear is the gear train composed of the gear sun gear which is fixed or rotates around the fixed center and the. Types of gear train and velocity ratio calculation. Sun gear is located at the center that transmits torque to planet gears orbiting around the sun gear. Following are the different types of gear trains, depending upon the arrangement of wheels. Sun gear and planet gear pdf lecture epicyclic gearing wikipedia. Introduction to gear trainsintroduction to gear trains most of the pictures and animations are from norton design of machinery. Pdf dynamic features of planetary gear train with tooth errors. For example, if the sun gear has 20 teeth and the ring gear has 60, the planetary gear has 80 teeth. Calculating load on planetary gear from driving torque. Plane t a r y gear tra i n s consis t o f the follo w i n g.
Notice how the planet gears roll on and revolve about the sun gear. Selfcentering characteristics of floating sun gear in a startype planetary gear train. The sun gear is located at the center, and transmits torque to the planet gears that orbit around it. Example 2 a compound epicyclic gear train overdrive has sun, small planet and large planet gears with 21, 15 and 24 teeth respectively. 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. The simple planetary gearbox comprises of the coaxial sun gear, planet carrier and outer gear subassemblies, and is combined with the planet gears rotating at. I also know the initial driving torque of the sun gear. The input shaft was modelled as a cantilever beam carrying the weight of the. G codes are basically plain text files which specify progressive positions of all axes of the cnc. Motion analysis on planetary gear train using multibody. 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. Sometimes, two or more gears are made to mesh with each other to transmit power from one shaft to another.
Calculate gear ratio by dividing the number of teeth on the driven gear by the. A simple but very common epicyclic train is the sun and planet epicyclic train, shown in the figure at the left. Two cases 1 dof when the sun is constant and planet is roatating as well as revolving around sun and arm rotating. Choosing which piece plays which role determines the gear ratio for the gearset. However, the proposed approach of regulating the installment of planet gears permits an integrated function of reduced transmission errors and a minimized backlash magnitude fig. The comparison of planetary gear system over helical gears systems is done on the basis of volume, weight and torque density keywords.
Patel institute of engineering, vitthal udyognagar abstract. In the solar system the planets revolve around the sun. Since all the three stages in the gear train are identical optimization of one stage is enough for reducing the complexity. When there are three or more planets, as is the usual case, care must be made to make sure the teeth of both planets can engage. This is because the planet carrier circled the sun gear once in the same direction as it was spinning, subtracting one revolution from the sun gear. These gear arrangements give different speed ratio options.
Dec, 2016 epicyclic gear trains are generally used for automatic transmission, overdrives, and final drives. Gear train with sun, planet, and ring gears matlab. Sep 15, 2014 dynamic features of planetary gear train with tooth errors. The planetary gear set, also known as the epicyclic gear train, is one of the most important and interesting inventions in engineering.
Methodology of design the design of planetary gear trains consists of following steps. For concepts b and c the center distances of both gear pairs must be equal, thus enabling both planet gears to be connected to one stepped planet gear shaft assuming the same normal module for both gear. A planetary gear train is very much like our own solar system, and thats how it gets its name. The gear ratios between the planetary train members cannot be calculated in the same way as gears trains with. An outer ring with inwardfacing teeth that mesh with the planet gear or gears. Planetary gear system is an assembly of gears where one or more planet gears revolve around a gear placed at centre named sun gear and a ring gear encircles the. A carrier connected to a drive shaft holds the planet gears. Pdf the paper presents an epicyclic gear train dynamic. The zar5 planetary gearing calculation program calculates the geometry and strength of sun, planet and ring gear spur or helical, involute teeth according to iso 6336, iso 28, din 3960, 3961, 3967 and 3990. The angular speed of the planet carrier can be found since we know the.
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. 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. Join the grabcad community today to gain access and download. The gear sets are referred to as the front and rear gear set. With the motion of the beam, this revolved around, and turned, the sun, a second rotating cog fixed to the drive shaft, thus generating rotary motion. 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. Calculate gear ratio by dividing the number of teeth on the driven gear by the number of teeth on the driving gear. In contrast to a ravigneaux, a simple planetary gear train has two concentric gears. Holds one or more peripheral planet gears, of the same size, meshed with the sun gear. Planetary gear trains are one of the main subdivisions of the simple epicyclic gear train family. This planetary gear train consists of a sun gear yellow. Simple planetary gear trains have a sun gear, a ring, a carrier, and a planet. Illustrated below is a typical epicyclic gear train. With the central gear fixed, a pinion rotates about it as a planet rotates about its sun, and the gears are named accordingly.
In order to achieve the above objective, methodology of design used is explained in next point. The epicyclic gear train consists of the sun gear a which is in mesh with the planet gear b. Pdf on aug 18, 2014, amar kumar and others published epicyclic gear train mechanism find. Planetary gear design a planetary gear system, also referred to as epicyclic gearing, consists of three elements a sun gear, one or more planet gears, and a ring gear. In this video solve numerical problem related to epicyclic and sun and planet gear train. The sun gear, the arm, or the ring gear may be input or output links. The ravigneaux gearset is a double planetary gear set, invented by pol ravigneaux, who filed. Zar5 calculates the tooth contact for gear pair sun planet and planet ring gear. This block models a gear train with sun, planet, and ring gears. This project dealt with the selection of materials for a harmonic planetary gear system. In this case, the planet gears have 12 teeth, the sun gear has 18 and the ring gear has 42 teeth. Sun and planetary gear train, 3d printing, lithography.
Planetary gears, gear train, is 4460, torque density. The gear have more than one gear on the shaft in any epicyclic gear trains, there is called compound epicyclic gear train. Pdf selfcentering characteristics of floating sun gear in. Design, analysis and optimization of planetary gearbox. Planetary gear is one of the epicyclic gear, which is a gear system consisting of one or more outer gears, or planet gears, revolving about a central, or sun gear. Determine the following if the engine drives the input planet carrier.
The inputand output shaftsare coaxial andthe inputand output 1 torques are assumedto be coaxialwith these shafts. A compound configuration for planetary gear train is selected and an optimization study is. The behaviors of dynamic load sharing characteristics. Rename sun i to sun i and clear the flag for input of speed. The solution of differential governing equation of motion is determined by applying the fourier series method. Ports c, r, and s represent the shafts connected to the planet gear carrier, ring gear, and sun gear. Kinematics of planetary gear trains angular velocity relations in a planetary train, the sun, carrier and ring rotate on coaxial shafts. Lecture 8 planetary gear train planetary gear trainspgt. One shaft is called sun gear shaft and the other shaft is called planet carrier shaft. This has become an epicyclic train with a sun gear and a planet gear orbiting around the sun, held in orbit by the arm.
One of the planetary gearsets from our transmission has a ring. Multi objective optimization of planetary gear train. Planetary gear with two sun gears and two planet gear sets. Such a combination is called gear train or train of toothed wheels. Pdf catalog available strength calculation available. Table 1 comparison of parallel shaft vs epicyclic gear trains. In the toothed formation sun and planet gears are externally mesh and ring gear is internally meshed.
Dynamic load sharing characteristics and sun gear radial. In the first three types of gear trains, the axes of the shafts over which the gears are. Typically, the arm and the sun gear will each be driven in some direction at some velocity. Design, load analysis and optimization of compound epicyclic gear trains syed ibrahim dilawer1, a planetary or epicyclic gear trains comprises of one or more planet gears revolving around a sun gear. Peripheral gears, of the same size, meshed with the sun gear and annulus. Pinion gear 8 pitch diameter 4 planet carrier 11 planetary gear set 11 power transfer unit 16 rearwheel drive rwd ring gear 11 spiral bevel gear 6 spur gear 5 sun gear 11 torque 2 torque converter 11 transaxle transfer case 16 transmission 8. In a compound epicyclic gear train as shown pdfinancialcorp com in the figure, has gears. Three planetary gears are used for mechanical reasons. Structure and analysis of planetary gear trains prof. Planetary gear train accessscience from mcgrawhill education. In many cases, one of these inputs will be zero velocity, i. Feb 28, 2017 the planetary gear set, also known as the epicyclic gear train, is one of the most important and interesting inventions in engineering. Design, modelling and analysis of a 3 stage epicyclic planetary reduction gear unit of a flight vehicle k akhila1 and m amarnath reddy2. On completion of this short tutorial you should be able to do the following.
The derivation for gearing ratios between sun gear, planet carrier and ring gear motions are given in the attached excel file. This is a simple, configurable, epicyclic planetary gear train created in creo parametric 3. They are great speed variation mechanisms, and are often. In a simple planetary gear train the pinions mesh simultaneously with the two coaxial gears see illustration. 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. Structure and analysis of planetary gear trains pdf. The ravigneaux set has two sun gears, a large sun and a small sun, and a single. Since the sun gear the largest gear is fixed, the dof of the above mechanism is one.
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