Challenge

Planetary Gear

JJeet Rathod11 Jun 2020

Aim :- Motion analysis of the planetary gear , To Design the Planetary Gear & to run a simulation for it.

Objective :-

for the following inputs provided designing the Planetary Gear
for the input parameters , run a simulation on the following cases
calculate the pitch circle diameter and the number of teeth for the planet gear
Obtain the plot/graph for Angular Velocity of the fixed part.

Input Parameters :-

Ring Gear :-
- Module = 2.5 (must use the metric system in design modeler)
- Number of teeth = 46

Sun Gear :-
- Number of teeth = 14
Input Speed of the Gear = 200 rpm.
Number of planet gears = 4

to run a simulation on the following cases,

Sl.No	Input	Output	Fixed
1	Sun Gear	Carrier	Ring Gear
2	Ring Gear	Carrier	Sun Gear
3	Sun Gear	Ring Gear	Carrier

Formula :-

Pitch circle dia (PCD) = NO of teeth * Module

Outer dia = (NO of teeth + 2 ) * Module

NO of teeth = `(PCD ) / (MODULE)`

Calculations :-

For Ring gear

PCD = 46*2.5

= 115

For Sun Gear

PCD = 14*2.5

= 35

Now,

For planetary Gear

`PCD of PLANETARY Gear = (PCD of RING Gear)/2 -(PCD of SUN Gear)/2`

= `115 / 2 - 35 / 2`

= 40

To find Number of teeth in Planetary Gear we use formula as

`NO. of. Teeth. On . PLANETARY. Gear = (PCD. OF. PLANETARY. GEAR) / (MODULE)`

= `40/2.5`

= 16

Theory :-

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 circle 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.

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.

Design Parts & Assembly :-

Ring Gear :-

Sun Gear :-

Planetary Gear :-

Carrier :-

Final Assembly :-

Explanation :-

Software used solidworks-2016
Starting the assembly directly and using the toolbox library select the ansi metric , select the ring gear and spur gear parts and start the process
The fallowing parts are shown in the above snap
provide the module , PCD , outside dia , No of teeth ,etc and the values for the following
The next step is to assemble the all parts to obtain a motion between them
Now we need to part the carrier for the gear assembly , so the dimensions used for the gears are used for the carrier to better fit the gears on the carrier.
Now Assemble the parts using proper mate command & also with the help of the three planes,
Now it’s time for the motion study, as asked in the challenge using the motor to rotate the gears and to obtain the simulation for the above given cases.
Using the solid body contact and providing 200 rpm speed for the motor
Providing the timeline for the motion study and calculate the motion study. For say 10 , 15 , 20 seconds thus this will create motion analysis of the Gear mechanism and desired simulation/animation of the motion is created
Lastly use the plot/figure function to obtain graphs for the angular velocity w.r.p to time for the output for each case

Result & Conclusion :-

Thus we have studied the motion analysis of the planetary gear mechanism and obtained the simulation for the cases given in challenge
Also designed the carrier for the gear assembly and assembled all the parts and obtained the motion study
Also obtained the graphs/plots for the output cases .

- The assembly and parts are provided in the below drive link

https://drive.google.com/drive/folders/1TyypzcUQcGtTPRHM032G7HltAPOy1bFe?usp=sharing

- for the three cases of the gear motion the video is provided below & link is also given below

Case 1 - https://youtu.be/Ojizy5NsS6w

Case 2 - https://youtu.be/7fr5Mi9ynuw

Case 3 - https://youtu.be/-lkonNO2-lA

- The plots obtained for the output cases are shown below

CASE 1 - Carrier output , Ring gear fixed

CASE 2 - Carrier Output , Sun gear fixed

CASE 3- Ring gear Output , Carrier fixed

Gear Simulation Video :-

CASE 1 - Carrier output , Ring gear fixed