Planetary Gear

AIM:  To design the planetary gear and to do motion analysis by giving inputs and then get the outputs.

OBJECTIVES:  

• To calculate the pitch circle diameter and the number of teeth for the planet gear.
• To do motion analysis by using different input parameters and then running the stimulation for different cases.

INTRODUCTION:

PLANETARY GEAR:

• In a manual transmission, different gear ratios are obtained by sliding the gears into mesh.
• Torque flow must be momentarily interrupted before the gears are shifted (use clutch) With an automatic transmission there is no driver- operated clutch, so gear shifts are not made by sliding gears into mesh.
• Automatic transmissions use a planetary gear set system that does not require an interruption of torque flow to change gear ratios.
• Nearly all automatic transmissions rely on planetary gear sets to transfer power and multiply engine torque to the drive axle.
• A simple planetary gear set consists of three parts:
  1. sun gear,
  2. Planet carrier
  3. ring gear
• All gears in a planetary gear set are in constant mesh. The torque flow through a planetary gear set, both input and output occurs along a single axis.

INPUTS:

• The module(m) is the ratio of reference diameter (or) pitch  diameter to the number of  teeth

             `m=d/T`             

             Here,

                      m=module

                       d=pitch circle diameter

                      T=number of teeth

• RING GEAR

Module (m) = 2.5

Number of teeth (T) = 46

Pitch circle diameter (d) =m*T =2.5*46 =115

• SUN GEAR:

Module (m) = 2.5

Number of teeth (T) = 14

Pitch circle diameter (d) = m*T =2.5*14 =35

• PLANET GEAR:

Module (m) = 2.5

Number of teeth (T) =?

Radius of Ring gear                   =            Radius of sun gear        +      Diameter of planet gear

      `((m*T)/2)_(RING)`           =          `((m*T)/2)_(Sun)`         +    `(m*T)_(PLANET)`      

Since module is same,

Number of teeth of Ring gear = Number of teeth of Sun gear + 2* Number of teeth of planet gear

                                46       =         14+2* 

                                           = 16

So, pitch circle diameter (d) =m*T =2.5*16 =40

DIFFERENT CASES:

Sr.no	Input	Output	Fixed
1	Sun gear	Carrier	Ring gear
2	Ring gear	Carrier	Sun gear
3	Sun gear	Ring gear	carrier

• Input- Rotary Motion given to that part as input.
• Output- After motion analysis, Angular Velocity of that part is plotted as a graph.
• Fixed- Make that particular component as a fixed part.

3D MODELS:

• Internal spur gear:

• Planetary gear:

• Sun gear:

• Carrier:

• Assembly:

SETUP STUDY:

• The first thing that we design is the carrier, based on the inputs the carrier is designed.
• Then in the assembly section we insert the Carrier and the based on the inputs we use the inbuilt gear models and insert the sun, ring, planet gear.
• Giving proper constraints we create the assembly.
• Further after making the assembly we go for the motion analysis.
• According to the different cases mentioned as above, we start with fixed ring gear case.
• In the motion analysis we start with giving the rotary motor to the sun gear (as mentioned in above case) and then giving solid body contacts, after the start the calculations of the motion and create a proper motion analysis.
• Then we go for getting the plot for angular velocity of the carrier.
• Further we follow the same procedure for second and third case respectively and get the results.

OUTPUT PLOTS:

Case 1: Ring gear is fixed, sun gear is used for input and carrier is used for output.

Plot:

Solidworks  plot:

So in this plot we can see that after achieving a particular angular velocity thereafter the angular velocity is slightly fluctuating with respect to time.

Excel Plot:

Animation:

https://www.youtube.com/watch?v=PjljRoD4Bc8

Case 2:  Sun gear is fixed, Ring gear is used for input and carrier is used for output.

Plots:

Solidworks  plot:

So in this plot we can see that after achieving a particular angular velocity thereafter the angular velocity is slightly fluctuating with respect to time.

Excel Plot:

Animation:

https://www.youtube.com/watch?v=mQAVcT-SuU4

Case 3:  Carrier is fixed, sun gear is used for input and Ring gear is used for output.

Plot:

Solidworks  plot:

So in this plot we can see that after achieving a particular angular velocity thereafter the angular velocity is slightly fluctuating with respect to time.

Excel Plot:

Animation:

https://www.youtube.com/watch?v=R1Nj4g8lJJk

Conclusion:

So we were able to do the motion analysis of the planetary gear by making the parts and assembly of it. Also we were able to make the plots for angular velocity for different cases.

Drive Link:

https://drive.google.com/drive/folders/1sMhyKJq6sHW3SBuo4MXqHH2kR5aDR94-