Planetary Gear
1.AIM - Motion analysis on the planetary gear Assembly with a carrier and to perform motion analysis for different configurations of the gearset and to compare the angular velocities.
2.OBJECTIVES :
- model the ring gear using toolbox in SolidWorks.
- model the sun gear using toolbox in SolidWorks
- model the planetary gears using toolbox in SolidWorks
- model carrier for planetary gears
- model a shaft for the sun gear
- Perform motion analysis for 3 configurations of the system
3.CASES :
| Cases | Input | Output | Fixed |
| 1 | Sun Gear | Carrier | Ring Gear |
| 2 | Ring Gear | Carrier | Sun Gear |
| 3 | Sun Gear | Ring Gear | Carrier |
4.Introduction :(Theory)
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.
Planetary gears are often used when space and weight are an issue, but a large amount of speed reduction and torque are needed. This requirement applies to a variety of industries, including tractors and construction equipment where a large amount of torque is needed to drive the wheels. Other places you will find planetary gear sets include turbine engines, automatic transmissions, and even electric screwdrivers.
5.GIVEN DATAS :
Ring Gear
Module = 2.5 (You must use the metric system in design modeller)
Number of teeth = 46
Sun Gear
Number of teeth = 14
Input Speed of the Gear = 200 rpm.
Number of planet gears = 4
6.FORMULAS USED :
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
Dia of ring / 2= Dia of planetary gear + Dia of sun gear / 2
7. 3D MODELS :
PLANET GEARS :
RING GEAR :
CARRIER GEAR :
SUN GEAR :
ASSEMBLY :(PLANETARY GEAR SET )
8.Motion analysis -
Motion analysis is done by considering above three cases at Input speed = 200 rpm.
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.
RESULT 1 : From the above graph, it can be observed that angular velocity at input is 60 deg/sec and at output is 14 deg/sec. Therefore, in this case, the planetary gear drive acts as reduction gear with gear ratio 0.233 : 1 ,When the input is given to the sun gear and output is obtained at carrier keeping ring gear fixed then, the planet gear not only rotate about their axis but also forced to roll on the inside of the ring gear since it is fixed. This results in low speed and high torque transmitting capacity.
ANIMATION :
https://drive.google.com/file/d/1Ws7M2W9eDcI-EH3VB1GlktH6YrPP3NI0/view?usp=sharing
Case 2: Input is given to ring gear keeping sun gear fixed
RESULT 2 :When the input is given to ring gear and output is obtained from the carrier keeping the sun gear fixed then, angular velocity is maximum since diameter of ring gear is large and planet gears are small so, when large gear meshes with a small gear the velocity is maximum at small gear because velocity ratio is high.
From the above graph, it can be observed that angular velocity at input is 60 deg/sec and at output is 43 deg/sec. Therefore, in this case, the planetary gear drive acts as reduction gear with gear ratio 0.716 : 1.
ANIMATION :
https://drive.google.com/file/d/1fNrrhnTDBczJvcsFBqHANJlc9bDY3IHx/view?usp=sharing
CASE 3 : Input is given to sun gear and fixed carrier gear :
RESULT 3 :When carrier is fixed and output is obtained at ring gear then, planet gear rotate only about axis and transmit motion from sun gear to ring gear and ring gear is big in diameter the angular velocity achieved is less.
From the above graph, it can be observed that angular velocity at input is 60 deg/sec and at output is 20 deg/sec but in opposite direction. Therefore, in this case, the planetary gear drive acts as reverse & reduction gear with gear ratio 0.333 : 1.
ANIMATION :
https://drive.google.com/file/d/1OoL-MGfNM13rwyyHNLT9Qggwnt1hasO7/view?usp=sharing
PARTS AND ASSEMBLIES LINK :
https://drive.google.com/drive/folders/1uJiDPc3p8du7ZwTVEE6ynrEY8bwn3MK1?usp=sharing