MBD Project 2 : Planetary Gear Simulation
Objective :
To design and simulate Planetary gear and motion analysis for following cases.
1. Sun Gear(As Input), Carrier(As Output), Ring Gear(Fixed)
2. Ring Gear(As Input), Carrier(As Output), Sun Gear(Fixed)
3. Sun Gear(As Input), Ring Gear(As Output), Carrier(Fixed)
Theory: Planetary gear :
An epicyclic gear train (also known as planetary gear) consists of two gears mounted so that the center of one gear revolves around the center of the other. A carrier connects the centers of the two gears and rotates to carry one gear, called the planet gear or planet pinion, around the other, called the sun gear or sun wheel. The planet and sun gears mesh so that their pitch circles roll without slip. A point on the pitch circle of the planet gear traces an epicycloid curve. In this simplified case, the sun gear is fixed and the planetary gear(s) roll around the sun gear.
An epicyclic gear train can be assembled so the planet gear rolls on the inside of the pitch circle of a fixed, outer gear ring, or ring gear, sometimes called an annular gear. In this case, the curve traced by a point on the pitch circle of the planet is a hypocycloid.
The combination of epicycle gear trains with a planet engaging both a sun gear and a ring gear is called a planetary gear train. In this case, the ring gear is usually fixed and the sun gear is driven.
Data Used :
Ring Gear
Module = 2.5
Number of teeth = 46
Sun Gear
Number of teeth = 14
Input Speed of Gear = 200 rpm.
Number of Planet Gears = 4
Calculation :
Module = Pitch diameter / No. of Teeth
`m= d/z`
Ring gear pitch diameter `d_{r i ng}` = `m*z` = 2.5 * 46 = 115
Sun gear pitch diameter `d_{sun}` = `m*z` = 2.5 * 14 = 35
Planet gear pitch diameter `d_{plan et}`= `(d_{ri ng} - d_{sun})/2` = `(115 - 35) / 2 = 40`
Number of teeth on Planet gear = `d/m = 40/2.5 = 16`
Design Data :
No. of teeth Pitch Diameter
Ring gear 46 115
sun gear 14 35
planet gear 16 40
Gear Design :
By using toolbox gears are directly imported and assign the value of No. of teeth and Pitch Diameter to them.
To mate this gear we sketch pitch circles and give them distance mate and concentric particular gear to particular circle.
Following are 3D design made in SolidWorks.
1. Sun Gear
2. Planet Gear
3. Ring Gear
4. Carrier
5. Assembly
Motion study in SolidWorks :
In solidworks software motion feature is use to analyse the motion of the models.
According to there use in solidworks they are diveide into three categories.
1. Animation
2. Basic Motion
3. Motion Analysis
Animation creates simple visuals of model movement by considration of mass and gravity effect. Basic motion use for considration of extra layer of complexity by taking effects of mass, spring and physical collision detection. Motion analysis is use for more advance and wider range by consideration of various forces and there effects i.e. impact effect, damping effect,momentum etc.
Motion Analysis Steps :
1. Active motion analysis Add-on from solidworks add-ons.
2. After that select 'Motion Analysis' from 'Type of study'.
3. Then provide motor to the input gear(according to case) by using motor feature.
4. After that provide contacts between gears and carrier using Contact feature. In this feature, material for gear and carrier is also provide.
5. From motion study property frame per second for the study is can be adjusted according to requirement.
6. After including all the required settings, the calculation of motion analysis is done by clicking on calculation button.
7. 'Result and plots' option is then use to generate various plots and result of the analysis at various points of model.
Result : Input speed 200 rpm.
Case 1 : Sun Gear(As Input), Carrier(As Output), Ring Gear(Fixed)
Angular velocity of Carrier is ploted as output :
From this plot it is shown that as increase in the speed of sun gear with time, the velocity of carrier is increasing with time. it is show that linearly angular velocity is increasing.
Animation case 1 : Simulation run at 0.1x speed
Case 2. Ring Gear(As Input), Carrier(As Output), Sun Gear(Fixed)
Angular velocity of Carrier is ploted as output :
From this plot it is shown that as increase in the speed of ring gear with time, the velocity of carrier is increasing with time. it is show that linearly angular velocity is increasing.
Animation case 2 : Simulation run at 0.1x speed
Case 3. Sun Gear(As Input), Ring Gear(As Output), Carrier(Fixed)
Angular velocity of Ring Gear is ploted as output :
This plot show that velocity of ring gear is first increase with very high rate and then it is behave as approximate constant.
Animation case 3 : Simulation run at 0.1x speed
Conclusion :
Successfully design the planetary gear and conducted motion study. From this plot we can see how angular velocity changes with time.
Part Design Link :
https://drive.google.com/drive/folders/1MHIrhs8PRz4cafR4BKtrs0brQZC0b6VM?usp=sharing