Planetary Gear
Aim - Motion analysis on the planetary gear Assembly with a carrier.
Objectives -
- To create 3D models for all parts like Spur gears, Ring gears and Carrier.
- To perform motion analysis by rotating the input gear at 200 rpm.
- To obtain a plot for Angular velocity of the output by applying below 3 cases.
- To export the results to a spreadsheet.
Components - 1 sun gear
4 planetary gears
1 ring gear
1 carrier.
Three Cases are -
|
Study number |
Input |
Output |
Fixed |
|
1 |
Sun gear |
Carrier |
Ring gear |
|
2 |
Ring gear |
Carrier |
Sun gear |
|
3 |
Sun gear |
Ring gear |
Carrier |
THEORY -
An epicyclic gear train (also known as planetary gear) consists of two gears mounted so that the centre of one gear revolves around the centre of the other. A carrier connects the centres of the two gears and rotates to carry one gear, called the planet gear, around the other, called the sun gear. 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.
A planetary gear set is made up of three types of gears; a sun gear, planet gears, and a ring gear. The sun gear is located at the center, and transmits torque to the planet gears, which are typically mounted on a moveable carrier. The planet gears orbit around the sun gear and mesh with an outer ring gear. Planetary gear systems can vary in complexity from very simple to intricate compound systems, depending on the application.
Calculation -
The module(m) is the ratio of Pitch diameter to the number of teeth.
m=d/T
where, m = module
d = pitch circle diameter
T = number of teeth
The module is the same for all the gears.
The relation between the pitch circle diameter and no. of teeth is as follows -
D = m * t
D = pitch diameter
m = module and t = no. of teeth
Dia of ring / 2= Dia of planetary gear + Dia of sun gear / 2
115/2 = D.P. + 35 / 2
D.P. (Dia of planetary gear) = 57.5 -17.5 = 40mm
|
Type of gear |
Pitch Diameter |
Module |
No. of teeth |
|
Sun Gear |
35 mm |
2.5 |
14 |
|
Ring Gear |
115 mm |
2.5 |
46 |
|
Planetary Gear |
40 mm |
2.5 |
16 |
3D Modeling and Assembly -
For creating gear from Toolbox -
Go to design library - Toolbox - ANSI metric - Power transmission - gears
For sun and planetary gears choose Spur gear
For Ring gear to choose Internal Spur Gear
Pressure angle = 20 degree
Face Width = 20 mm
Carrier 3D geometry -
Whole assembly -
OUTPUT -
Motion analysis -
Motion analysis is done by considering above three cases at Input speed = 200 rpm.
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Case 1- Input is given to sungear by motor at 200 rpm and keeping ring gear fixed.
The plot of an angular velocity of the output i.e carrier against time.
The Animation of case 1 :
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Case 2- Input is given to ring gear by motor at 200 rpm and keeping sun gear fixed.
The plot of an angular velocity of the output i.e carrier against time.
The Animation of case 2 :
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Case 3- Input is given to sun gear by motor at 200 rpm and keeping carrier fixed.
The plot of an angular velocity of the output i.e ring gear against time.
The Animation of case 3 :
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For viewing assembly and parts of this project then click on the below drive link :-
https://drive.google.com/drive/folders/1nUvCV11Oh9rIpW6wZzxTTuxuuizpb5xN?usp=sharing