Planetary Gear
Objective
Constructing a planetary gear system with four planet gears fixed to a carrier and analyzing the angular velocities of the input and output gears.
Introduction
The planetary transmission system (or the Epicyclic system as it is known), consists of mid-range solar radiation, ring gear and numerous rotating planetary gears between these. This concept of conjunction explains the term motion of the planet, as the planets of the planet orbit around the sun's galaxy just like in the starry planets the planets orbit the sun.
The benefit of planetary transmission is determined by the load distribution over most of the planet's gears. So it is possible to pass the maximum torque using the built-in design.
In the model developed here, all gears are permanent gears.In the model created here, the gears are all spur gears.
Dimensions & Conditions
Module = 2.5 for all the gears.
Internal Gear(Ring gear), Number of teeth = 46
Sun Gear, Number of teeth = 14
Number of planetary gears = 4
Speed of Input gear = 200rpm
From Calculations,
For Ring gear:
Module(m) = 2.5
Number of teeth(T) = 46
So, Pitch circle diameter(d) = m*T = 2.5*46 = 115
Diameter of Sun gear =
Module(m) = 2.5
Number of teeth(T) = 14
So, Pitch circle diameter(d) = m*T = 2.5*14 = 35
Diameter of 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
No. of teeth of Ring gear = No. of teeth of Sun gear + 2 × No. of teeth of Planet gear
46 = 14+2*Tplanet
Tplanet = 16
So, Pitch circle diameter(d) = m*T = 2.5*16 = 40
Conditions for Analysis
|
Sl.No |
Input |
Output |
Fixed |
|
1 |
Sun Gear |
Carrier |
Ring Gear |
|
2 |
Ring Gear |
Carrier |
Sun Gear |
|
3 |
Sun Gear |
Ring Gear |
Carrier |
The link to the Parts and the assembly:
https://drive.google.com/drive/folders/1rl_pC-MbD05E0td4cbMZDhr0tb8NwRVe?usp=sharing
Individual Gears
Sun Gear
Planet Gear
Internal Gear
Carrier
Results
1) Internal Gear(Ring gear) is fixed, Sun gear is input gear and the carrier is output.
Input
Output
Link to the animation: https://youtu.be/iBG0fLGAYK4
2) Sun Gear is fixed, Internal gear(Ring gear) is input gear and the carrier is output.
Input
Output
Link to the animation: https://youtu.be/kw83H9oBCz4
3) Carrier is fixed, Sun gear is input gear and the Internal gear(Ring gear) is output.
Input
Output
Link to the animation:
Conclusions
- Output speed is lower than input speed in all cases.
- Where the Sun gear is an input gear, the required speed is obtained over a short period of time. But if gear rings are the input gear, the required speed is obtained in accordance with the timing.
- The output speed has less disturbance due to the collision between the gear teeth.