Sun and planet gear mechanism with base lego technic pic 1. Gear meshing analysis of planetary gear sets with a. Schedule and reading assignment quiz bolted joint qualifying thursday march 19th topics belts friction drives gear kinematics reading assignment read. And it can be wildly used in industry, such as printing lathe, automation assembly. G codes are basically plain text files which specify progressive positions of all axes of the. Their can be either three 3 or four 4 planet gears in the planet carrier. This causes the ring gear to rotate in a direction opposite that of the sun. It is possible that it automatically decides combination and center distance of the troublesome teeth number, etc.
The answer lies in the mechanism called a planetary gear mechanism. Lightweight design for planetary gear transmissions. In this simplified case, the sun gear is fixed and the planetary gear s roll around the sun gear. Normally, the ring gear is stationary, causing the planets to orbit the sun in the same rotational direction as that of the sun. Planetary gear sets may be the most interesting mechanism in the gear world. For this stage, with the sun as input, planet carrier as output, and the ring gear fixed, the formula is. This tutorial is the assembly instructions for the rotating movement by a planetary gear mechanism. Its a video for the explanation of the motion of a planetary gear mechanism. Gear 5 has 30 teeth and is keyed to the same shaft as gear 4. There are totally eight planets in the planetary gear. Pdf despite a large body of analytical work characterizing the dynamic.
So named for the four planet gears orbiting the central sun gear. Intro planetary gears also refer as epicyclic gearing consisting three elements sun. The planetary gear and mechanical paradox gear design system software can do the design of the planet gear and the mechanical paradox gear easily. Here, n, the number of planet gears, is taken as 3 throughout the paper. Eventually it will be used to drive an archimedes screw as a lifting mechanism for a marble machine. The system consists of a highspeed part h, a lowspeed part l, a sun gear s, a ring gear r, n planet gears p and a carrier c. In the case of a floating sun gear, the deviation of the position of the center of the sun gear o s is determined by two parameters, i. A typical application is the automatic transmission system of car. The carrier link 2 serves as the input to the train. From a kinematic point of view, what sets this mechanism apart is the kinematic constraint set between gear. Planetary gears are common in transmission systems, where they provide high gear ratios in compact geometries. 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. For this reason, this class of gear is often referred to as a planetary system. For this reason, this class of gear is often referred to as.
Mechanical paradox gear mechanism used in a large reduction gear. Either the sun or ring gears may be fixed, the other performs rotation about its axis fig. 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. The hexagonal holes in the sun should be pointing outwards. The planetary gear system of concern in this study is a singlestage 2kh type planetary gear set as shown in fig. Each planetary is driven by the ring gear, and output taken from the rotation of the planet gears about the sun gear. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear. A planetary gearbox with flexible pin design developed by itri taiwan. Apr, 2014 differential is an arrangement of gears which work together and allow the vehicle to take a turn smoothly.
Sun and planetary gear train, 3d printing, lithography. From a kinematic point of view, what sets this mechanism apart is the kinematic constraint set between gear pairs. Mount 3 planets onto carrier, secure each with a washer. When the rotating ring gear is mounted on top of the fixed ring gear, i. The sun and planet gear of james watt, actually invented by william murdoch, as a non patentinfringing alternative to the crankshaft for his rotative beam engines. The planet carrier keeps the gears equally spaced apart allowing them to evenly support the ring gear from the sun gear. It consists of two bevel gears sun gear and two bevel gears planet gear. Planetary gear trains are one of the main subdivisions of the simple epicyclic gear train family. Gear sets serve to transfer rotational motion and torque at a known ratio from one driveline axis to another. Sun gear p planet gear r ring gear a a r m ex ampl e. Each of these components can serve as the input, output, or can be held stationary.
The center distance of each gear pair of one concept sun planet gear or ring planet gear must be equal using a small number of teeth while also complying with further assembly rules will create a gear set with a number of teeth that meet the desired transmission gear ratio, with only a certain deviation. The angular speed of the planet carrier can be found since we know the. An advantages of planetary gear arrangement is they can transmit a lot of power from a small volume. If the gear is not splined to the shaft then the gear is supported by a bushing or needle bearings. Research laboratory new design and improvement of planetary. Calculate the number if teeth required in the ring gear for the ratio 5. Differential is an arrangement of gears which work together and allow the vehicle to take a turn smoothly. The sun gear rotates a few planet gears, which all simultaneously rotate a large internal gear, called the ring or annular gear. In the differential, bevel pinion gear is fixed to the propeller shaft which rotates the crown wheel. Design of machinery an introduction to the synthesis and.
We develop multilobbed cam profiles, the sun cam and the ring cam, which. Kinzel kinematics, dynamics, and design of machinery, 1999. Press the top part of the sun gear into the hole in the bottom part this should be a tight fit, but you may have to ream the opening a little. Illustrates how you can build your own custom planetary gear components from the simscape driveline planetary subcomponents library. Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer. The computeraided design cad files and all associated content posted to this website are created, uploaded, managed and owned by third party users. All the gears are mounted on their flexible shafts supported by rolling element. In a compound epicyclic gear train as shown pdfinancialcorp com in the figure, has gears. Nonlinear dynamics of a planetary gear system with. The action is epicyclic, because the centers of the planet gears revolve about the sun gear while the planet gears turn. This has become an epicyclic train with a sun gear and a planet gear orbiting around the sun, held in orbit by the arm. Each of these three components can be the input, the output or can be held stationary. Simple planetary gears have one sun, one ring, one carrier, and one planet set. Murdock also experimented with compressed air and in 1803 constructed a steam gun.
A planetary gear train with two or more than two planet gears, namely planet 1 and planet i, is considered for the derivation of the geometrical relation, as shown in fig. Other differential designs employ different numbers of planet gears, depending on durability requirements. 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. If you would like to give it a try all the instructions and files are below. A point on the pitch circle of the planet gear traces an epicycloid curve. Insert the carrier with the planets and sun on them into ring. Each cad and any associated text, image or data is in no way sponsored by or affiliated with any company, organization or realworld item, product, or good it may purport to portray. Other uses for gears how gear ratios work howstuffworks.
May 23, 2011 align the planet gears into the crown along with the bottom part of the sun gear. Subcategories this category has the following 4 subcategories, out of 4 total. Attach ring to front for stage 1 or to previously installed ring for stages 2, 3, etc. This block models a gear train with sun, planet, and ring gears. At the second stage, the planet carrier acts as the input for the second planetary gear set, the larger sun gear. The planet gears perform rotation with the carrier and about the carrier fig. Align the planet gears into the crown along with the bottom part of the sun gear. Transmission refers to the transfer of engine torque to another system. Ive put this project together as part of my learningtousealasercutter experiments. Mechdesigner can model simple, compound, epicyclic, planetary, compound planetary, and differential gear trains and systems.
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. The crown wheel has another unit called the differential unit. Planetary gear design pdf pin mechanism for planetary gear drives in wind turbines. Gear train with sun, planet, and ring gears matlab.
Epicyclic mechanisms have found wide applications in industry, especially in auto mobiles and robotics. The main components of a planetary gearbox include the sun gear, which is in the center of the gearbox, usually connected to the input shaft of the system. The planet carrier, annulus or ring gear, and sun can be fixed. Planetary gear mechanism by garyhodgson thingiverse. The planetary gear set, also known as the epicyclic gear train, is one of the most important and interesting inventions in engineering. The sun gear 1 serves as the output from the train and has a 1. 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. 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. 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. In many cases, one of these inputs will be zero velocity, i. One more design requirement must be specified to do the remaining calculations. Pdf analysis of stresses and deflection of sun gear by.
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. The following 17 files are in this category, out of 17 total. The efficiency is usually cited at about 97% for a single stage planetary gear box. Performance study and mathematical model of aerospace. Other articles where sunandplanet gear is discussed.
The kinematic scheme of loadsplit twostage planetary gear is shown in figure 1, which is composed of closed planetary gear train and differential planetary gear train. Choosing which piece plays which role determines the gear ratio for the gearset. Planetary gear ratio calculations this article also available in spanish. Determine how heat generation affects the efficiency and temperature of driveline components using thermal variants of 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. 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. Since the sun gear the largest gear is fixed, the dof of the above mechanism is one. As the differential carrier rotates, the changing axis orientation of the planet gears imparts the motion of the ring gear to the motion of the sun gears by pushing on them rather than turning. Design, analysis and optimization of planetary gearbox. The sun gear is located at the center, and transmits torque to the planet gears that orbit around it.
Finding the gear ratio is somewhat complicated because the planet gears revolve while they rotate. Notice that the sun and flywheel rotate twice for every circuit of the planet when they have a 1. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves. The gear sizes for the sun gear and the planet gear can be changed. Former basic units 1c planetary carrier and 1s sun gear are connected to units 2r inner ring and 2c planetary carrier of differential gear train, respectively. The application is designed primaly to support the design of multybody mechanisms.
Usually the sun gear has a metal shell cup shaped attached to it in order to allow the gear to be utilized. 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. In the case of a floating sun gear, the deviation of the position of the center of. 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. One full rotation of the ring gear green arrow results in 0. A carrier connected to a drive shaft holds the planet gears.
Planetary gear trains are common in industrial, automotive, and aerospace systems. Planetary gear drives are constituted by three main elements. Our design focused on the first of these, with a crank input for the sun gear and rotatable brackets with an output axle for the planet gears. 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. Life distribution transformation model of planetary gear system. Gear meshing analysis of planetary gear sets with a floating. The orbiting motion of the planets is transmitted to the output shaft by a planet carrier. The ideal positioning of the center of the sun gear o s coincides with the center of the annulus gear. Pdf design and conduct of precision planetary gear vibration.
By allowing both the planet carrier and the ring gear to rotate, a differential gear drive is produced, the output speed of one. 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. The planet and sun gears mesh so that their pitch circles roll without slip. Jan 12, 2014 this tactile and delightful looking mechanism is a planetary gear. Typically, the arm and the sun gear will each be driven in some direction at some velocity. Gear 1 is called a sun gear, gear 2 is a planet, link h is an arm, or planet carrier. For each planet the load acting on the two outer gears is reacted by the fixed gear 9 a full complement of planetary gears is used to distribute the load over a large number of. A gear train is two or more gear working together by meshing their teeth and. Analysis of dynamic behavior of multiplestage planetary. Sun gear planet gear outer ring planet carrier figure 3. Introduction to mechanisms carnegie mellon school of. Simscape driveline contains angular gears for transferring rotational motion and torque and linear gears, for transferring translational motion and force.
1100 306 400 278 465 625 908 690 800 242 439 1352 128 1369 757 1021 983 1032 1361 1319 871 1198 211 850 1401 1446 1249 989