Finite element method based analysis of planetary gear. Gears have a module of 5 mm and a 20 pressure angle. Design, analysis and optimization of planetary gearbox. Introduction to mechanisms carnegie mellon school of. 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. Rameshkumar 16 load sharing analysis of highcontractratio in spur gear. A planetary gear train is a little more complex than other types of gear trains. Yuksel 7 dynamis tooth load of planetary gear sets m. Design, load analysis and optimization of compound. The results indicate that a camcontrolled planetary gear train is of high mechanical. Torque applied radially onto the gears of a planetary gear train is transferred radially by the gear, without lateral pressure on the gear teeth. Force analysis for spur gears equation and calculator. An electric motor operates the planetary gear train via a belt multiplying the rotational speed of the planetcarrier up to a maximum of 6000 rpm, i.
Joint dynamic analysis of space manipulator with planetary. If the arm is the input and the planet is the output, the overall gear ratio is 31 3. Choosing which piece plays which role determines the gear ratio for the gearset. Nerantzis the load carrying capacity of gear transmissions depends strongly on design, material and operation conditions. Two forms of planetary gears of the bevel type are shown in figures 23 and 24. Planetary gearbox vibration signal characteristics analysis. Pdf dynamic analysis of planetary gear train based on adams. The system studied is thus symmetric around the ox axis. Free body diagrams of gear trains american society for. Planet gears are just idle gears from the force perspective, and the fbd is shown in fig. The load carrying capacity of gear transmissions depends strongly on design, material and operation conditions. Power and torque is transmitted when a tooth of an input gears exerts a force f n along the pressure line on the tooth of output gear see figure a.
Dynamic analysis of planetary gear train base d on adams. This study aims to carry out the frictional analysis of camcontrolled planetary gear trains through an illustrative example. A planetary gear train is very much like our own solar system, and thats how it gets its name. A twostage planetary gear stage is defined using the program. In a typical application, the drive power connects to the sun gear. Even if the prime mover engine and the vehicle as a whole on pneumatic wheels are modeled in a crude way, the different modes of planetary gear. Gear 3 is an idler to change direction of the output. This makes it impossible to study the influence of centrifugal effects that introduce an asymmetric force act. Example shaft a has a power input of 75 kw at a speed of rpm counterclockwise.
Planetary gearboxes are widely used in helicopters, wind turbines, mining machinery, and so forth. Design of machinery an introduction to the synthesis and. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which. With the rotation of each element of the gear train in hand, the overall gear ratio becomes easy. In this tutorial, we will show you an original and easyto. Figure 1 shows an epicyclic gear mechanism employing the ravigneaux gear set as the ratio change gear train where the rotating and band clutches are designed as c and b, respectively. Gear t e e t h n s1 6 n p1 19 n r1 4 8 n s2 6 n p2 19 n r2 4 8 tr. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear. The angular speed of the planet carrier can be found since we know the. Following are the different types of gear trains, depending upon the arrangement of wheels.
Dynamic analysis of planetray gear trains considering. The noload power losses produced by the planetary gear train are determined from direct torque measurements by a strain gauged sensor. The gear ratio formula for two meshing gears is simple and intuitive, while the gear ratio formula for the planetary mechanism is not. 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. Another class of gear train has wide application, the epicyclic or planetary train. 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.
In order to understand the fundamental nature of planetary gearbox. Previous investigators, for the most part, have not considered load variations which normally occur because of the elastic nature of the gear train elements. Planetary epicyclic gear ratios equations and calculators. Ports c, r, and s represent the shafts connected to the planet gear carrier, ring gear, and sun gear. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can rotate. Planetary gear train article about planetary gear train. Please start with the tutorial for shaft calculation to see how to introduce geometry and supports for single shafts. Analysis of planetary gear trains figure removed for reasons. Finite element method based analysis of planetary gear systems considering backlash and manufacturing deviations a. The planet gear in figure 23 rotates about a fixed bevel gear at the center of which is the driven shaft.
Adjusting for a pitch radius difference of, say, 3. Epicyclic gear train, pinhole position error, pin stresses, load sharing 1. Introduction the epicyclic gear train egt is known as planetary gear train pgt. Planetary gear train a mechanism for transmitting rotational motion by spur or bevel gears less often by. All 34 types can be derived from one general form of the simple planetary gear train. The analysis is restricted to the optimization of gear train through load analysis of the gears, pinions and annulus including the sun and plant gears, and finding out the optimal load conditions for the gear train to perform. In an epicyclic gear train, the axes of the shafts, over which the gears are mounted, move relative to a fixed axis. In order to estimate the loading capacity, the force distribution in the system members and, thereby, the statical indeterminateness of the system should be measured. Planetary gearbox vibration signal characteristics. The angular speed of the planet carrier can be found since we know.
If the carrier is acting as the input in the planetary gear system, rotating the ring gear while the sun gear is still, divide the number of teeth on the ring gear the driven gear by the number of teeth on the planetary gears the driving gears. Lets analyse the motion before and after the inversion with table 73. Problem no 2 on epicyclic gear train gear trains kinematics of machinery theory of machines duration. The deformation of gear tooth was separated into a global term. Sunyoung 17 failure analysis of a planetary gear train a. One of the planetary gearsets from our transmission has a ring gear with 72 teeth and a sun gear with 30 teeth. First, the equations for frictional analysis proposed in the previous study are presented. Then, the results of friction force and couples are obtained by numerical analysis. Each of these three components can be the input, the output or can be held stationary. The planetary gear train also provides stability due to an even distribution of mass and increased rotational stiffness. Epicyclic gear train is a gearing system consisting of one or more ring gears, or planet gears, revolving about a central, or sun gear.
For a more involved epicyclic gear train example, please refer to the epicyclic gear train example section. 4 problem of number of teeth, number of planet gears and planet gear spacing differential gear systems. In a planetary train at least one of the gears must revolve around another gear in the gear train. In this case, the planet gears have 12 teeth, the sun gear has 18 and the ring gear has 42 teeth. The planetary gear train with intermediate rollers possess a high loading capacity due to the multiple contact between their members.
Design, load analysis and optimization of compound epicyclic. This block models a gear train with sun, planet, and ring gears. A carrier connected to a drive shaft holds the planet gears. Gear train with sun, planet, and ring gears matlab.
There are four different ways that a planetary train can be hooked up. Analysis of load distribution in planet gear bearings. Usually the analysis is made considering constant torques applied to the input member. But in case of epicyclic gear trains, the axes of the shafts on which the gears are mounted may move relative to a fixed axis. The planetary gear train consists of two sun gears, two sets of pinion gears three in each set, two sets of annular internal gears and pinion carriers which support the pinion gears on pins. It is stated that the simple planetary gear train consisting of two central gears, one or more planet gears and one arm, has 34 different types. Relations between size and gear ratio researchgate. The force at the second ring gear mesh results from the output torque on the ring gear. Invert the planetary gear train mechanism by imagining the application a rotary motion with an angular velocity of h to the mechanism. Yet it remains an ongoing challenge to account for backlash and manufacturing errors, despite a definite need to do so. 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. Dynamics analysis sun gear applying newtons second law in rotation nslr to the sun gear, we have.
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. Similarly, the radial force acting on drive gear equals the axial force acting on driven gear. The structure and motion type of a planetary gearbox are more complex in comparison with a fixedshaft one, which makes condition monitoring and fault diagnosis of planetary gearbox a challenging issue in practical applications. Fbd of a planetary gear train a planetary gear train is a gear train that allows the input and output shaft to be coaxial. Frictional analysis of camcontrolled planetary gear. Epicyclic gear trains egts are commonly used in automatic transmission mechanisms to achieve a set of desired velocity ratios. 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. Teaching planetary gear trains with the aid of nomographs. Example shaft a has a power input of 75 kw at a speed of rpm counter clockwise. In summary, the planet gear outer ring is submitted to mesh forces f s, f t, m and roller contact loads q i. Jan 17, 2018 problem no 2 on epicyclic gear train gear trains kinematics of machinery theory of machines duration.
Working out planetary gear turns ratios working out the gear ratio of a planetary gear train can be. Force analysis spur gears equation and calculator engineers. H is the rotary velocity of gear i in the imagined mechanism. The radial force acting on the gear is given by w r w t tan. All the components are modelled in catia to check the assembly and the.
For all forward gears, power enters the gear train via the forward annular gear and leaves the gear train by the reverse annular gear. The force f n resolves into two components, the tangential f t, the radial component f r, which are related to the pressure angle. The gear b meshes with gear a and has its axis on the arm o 2, about which the gear b can. Introduction to gear trainsintroduction to gear trains. L where a gear a and the arm c have a common axis at o 1 about which they can rotate.
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