An epicyclic gear train consists of two gears mounted so that the center of one gear revolves. 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. Determine how heat generation affects the efficiency and temperature of driveline components using thermal variants of gear. Ive left it as a pdf file as, if you have, or have access to, a laser cutter then you will know how best to convert it for use on your particular machine. The gear sizes for the sun gear and the planet gear can be changed. The downloadable file is available as a link in the previous step. Kinzel kinematics, dynamics, and design of machinery, 1999. The center distance of each gear pair of one concept sun planet gear or ringplanet 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. One suggestion is to design a hightech salad spinner using an epicyclical gear mechanism. 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 effect of gear teeth on ring stiffness is ignored.
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. Then i connected one of the planet gears to a second pin mechanism along the same axis as the sun. Planetary epicyclic gearing is a gear system consisting of one or more outer gears planet gears revolving about a central sun gear. May 23, 2011 align the planet gears into the crown along with the bottom part of the sun gear. Since the sun gear the largest gear is fixed, the dof of the above mechanism is one. If the carrier is acting as the output in the planetary gear system, being rotated by the sun gear while the ring gear stays still, divide the number of teeth on the planetary gears the driven gear by the number of teeth on the sun gear the driving gear. The angular speed of the planet carrier can be found since we know the.
This project explores the use of plywood to make mechanical, decorative, and structural parts. If the sun gear isnt frozen, the relative motion is difficult to control. Either the sun or ring gears may be fixed, the other performs rotation about its axis fig. 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 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. Gear meshing analysis of planetary gear sets with a. Simscape driveline contains angular gears for transferring rotational motion and torque and linear gears, for transferring translational motion and force. Pdf selfcentering characteristics of floating sun gear in a star. Gear train with sun, planet, and ring gears matlab. Sun and planet gear mechanism with base lego technic pic 1. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear. First of all, its worth noting about internal gears. The sun gear and the planet gear are enclosed by ring gear. Planetary gear ratio calculations this article also available in spanish.
In many cases, one of these inputs will be zero velocity, i. 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. When a local fault occurred on the tooth of a planet gear, along with the system operating, the faulty tooth will mesh with the ring gear or sun. The combination of epicycle gear trains with a planet engaging both a sun gear and a. When you pull the arm or the planet, the mechanism has a. When the sun gear 1 is coupled to the axle, the first gear step of the stepped planet gears rolls off between the fixed sun gear 1, and the rotating ring gear. Comparing these results, we constructed a method of. 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. Planetary gear design pdf pin mechanism for planetary gear drives in wind turbines. Pdf a floating gear mechanism is often adopted in planetary gear design in order to share the load torque equally among planetary gears. How to i design a planetary gear with a gear ratio of 2. A hypocycloidal crank mechanism with a suntoplanet gear ratio d file size makes an animation smoother and thus better to read. Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer.
A wide variety of sun gear options are available to you, there are 1,237 suppliers who sells sun gear on, mainly located in asia. Align the planet gears into the crown along with the bottom part of the sun gear. And it can be wildly used in industry, such as printing lathe, automation assembly. In this simplified case, the sun gear is fixed and the planetary gear s roll around the sun gear.
The planet and sun gears mesh so that their pitch circles roll without slip. A hypocycloidal crank mechanism with a sun to planet gear ratio d sun gear and a planet gear orbiting around the sun, held in orbit by the arm. 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. Conceptual design of planetary gearbox system for constant. Each of these three components can be the input, the output or can be held stationary.
The mesh loads are assumed to act along the line of action and on the pitch radius r p. Lightweight design for planetary gear transmissions. Sunandplanet gear definition of sunandplanet gear by. Gear meshing analysis of planetary gear sets with a floating. They are great speed variation mechanisms, and are often. In the planetary gear system, the center axle and main axle are coincide with each other, so in order to make the ring gear, sun gear and the orbits of the planet gear concentric, we should have the concentric condition. The planetary gear set, also known as the epicyclic gear train, is one of the most important and interesting inventions in engineering. It was invented to bypass the patent on the crank, already held by james pickard. Typically, the arm and the sun gear will each be driven in some direction at some velocity. At the second stage, the planet carrier acts as the input for the second planetary gear set, the larger sun gear. Planet gears, external gears surrounding the sun gear, usually three or four of them are present shown in blue. Orrery a mechanical solar system model from plywood.
Pdf gearing is one of the most critical components in mechanical power. Most mechanism of planetary gear comes with compact design and high reductive gear ratio consisting of sun. For this stage, with the sun as input, planet carrier as output, and the ring gear fixed, the formula is. One full rotation of the ring gear green arrow results in 0. A gear train is two or more gear working together by meshing their teeth and. Other uses for gears how gear ratios work howstuffworks. Three planet gears are coupled to output shaft through a carrier.
Mount 3 planets onto carrier, secure each with a washer. Research laboratory new design and improvement of planetary. Insert the carrier with the planets and sun on them into ring. 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. One rotation of the ring gear green arrow results in 0. This block models a gear train with sun, planet, and ring gears. Attach ring to front for stage 1 or to previously installed ring for stages 2, 3, etc. Its a video for the explanation of the motion of a planetary gear mechanism. Other articles where sunandplanet gear is discussed. This tutorial is the assembly instructions for the rotating movement by a planetary gear mechanism. The hexagonal holes in the sun should be pointing outwards.
Ive put this project together as part of my learningtousealasercutter experiments. The parts are all laid out in a pdf file and then transferred to the laser cutter software. 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. The planet gears perform rotation with the carrier and about the carrier fig. The application is designed primaly to support the design of multybody mechanisms. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes. Gear sets serve to transfer rotational motion and torque at a known ratio from one driveline axis to another. Planetary gear trains are one of the main subdivisions of the simple epicyclic gear train family. In general, increasing the frame count within limits constrained by the file size makes an animation smoother and thus better to read. 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. 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. Motion periods of planet gear fault meshing behavior mdpi. Illustrates how you can build your own custom planetary gear components from the simscape driveline planetary subcomponents library.
So named for the four planet gears orbiting the central sun gear. The ideal positioning of the center of the sun gear o s coincides with the center of the annulus gear. 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. Analysis of load distribution in planet gear bearings. The arm carries the planet gears in orbit around the sun gear. Pdf analysis of stresses and deflection of sun gear by. Ports c, r, and s represent the shafts connected to the planet gear carrier, ring gear, and sun gear. In a compound epicyclic gear train as shown pdfinancialcorp com in the figure, has gears. A point on the pitch circle of the planet gear traces an epicycloid curve. Planetary gears are common in transmission systems, where they provide high gear ratios in compact geometries. Sun gear, an external gear in the middle of the gear set shown in yellow. In the case of a floating sun gear, the deviation of the position of the center of. 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. This instructable is about how to build a desktop orrery.
An orrery is a mechanical model of the movement and position of the planets in our solar syste. If the gear is not splined to the shaft then the gear is supported by a bushing or needle bearings. For example, one connection was a pin connection between the sun and the sun shaft, another to the planetary carrier, it just depended on the setup. Planetary gear drives are constituted by three main elements. This can be designed by the feeli ng which is the same as the equality position of planet gear.
Choosing which piece plays which role determines the gear ratio for the gearset. A carrier connected to a drive shaft holds the planet gears. When you pull the arm or the planet, the mechanism has a definite motion. The loads acting on the bearing outer ring are simplified as two equal and diametrically opposed loads representing, respectively, sun planet and ring gear planet meshes fig. The sun gear is located at the center, and transmits torque to the planet gears that orbit around it. The sun needs to be pushed hard into the following. Introduction to mechanisms carnegie mellon school of. Calculation of load distribution in planetary gears for an. The sun gear is located at the center of the gear train solar system. Usually the sun gear has a metal shell cup shaped attached to it in order to allow the gear to be utilized.
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