Planetary Gear
Aim :
Constructing a Planetary gear system with four planet gears and analyzing the angular velocities for different cases
Objective :
Design planetary gear with the following parameters:
- Ring Gear:
- Module = 2.5 (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
Simulation & Analysis of planetary gear system with the following conditions:
create the plots of outputs
Introduction:
Planetary Gear System or an epicyclic gear train is used to set different gear ratios by using three sets of the gears sun gear, planet gear, and ring gear.
All the planet gears are mounted to a single rotating member, called a cage, arm, or carrier where the output is obtained.
A planetary gear set is comprised of an outer gear ring that's called the ring gear. As they rotate inside of the ring gear, the planetary gears create pitch circles that can be formed into a gear train that, in turn, is hooked up to input and output shafts.
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.
Planetary gear systems are able to produce a lot of torque because the load is shared among multiple planet gears. This arrangement also creates more contact surfaces and a larger contact area between the gears than a traditional parallel axis gear system. Because of this, the load is more evenly distributed, and therefore the gears are more resistant to damage.
Calculation:
Module needs to be same for each gear for the law of gearing to satisfy.
Ring Gear
Module = 2.5
Number of teeth = 46
Sun Gear
Number of teeth = 14
Input Speed of the Gear = 200 rpm.
Number of planet gears = 4
Module =
For Ring gear PCD = 46*2.5 = 115
For Sun Gear PCD = 14*2.5 = 35
Now (PCD of Sun Gear)/2 + PCD of Planetary Gear = (PCD of Ring Gear)/2 which gives
PCD of Planetary Gear = 40
Number of teeth in Planetary Gear = 40/2.5 = 16
3D models
Ring Gear
sun gear
Planet gear
Carrier
Assembly of planetary gear system
Motion study
output Plots:
Case 1 :Fixing the Ring Gear, giving input to the sun gear and receiving output at the carrier
output
fixed ring gear
animation link :
https://www.youtube.com/watch?v=X4oCCFpg63s
Case 2 :Fixing the Sun gear, giving input to the Ring gear and receiving output at the carrier
output
fixed sun gear
Animation link:
https://www.youtube.com/watch?v=qL4YJfhNp9w
Case 3: Fixing the carrier, giving input to the sun gear and receiving output at the ring gear
output
fixed carrier
Animation link:
https://www.youtube.com/watch?v=_9JpOPaJMag
Conclusions:
The output speed is lower than the input speed in all cases.When Sun gear is input gear, the required speed is achieved within a short duration of time. But when ring gear is input gear, the required speed is achieved linearly with time.The output speed has small disturbances due to collisions between the gear tooth.
Drive link for parts :
https://drive.google.com/drive/folders/1YiTZr7Q6dEKpXRh3mATWAN_VsMAFM-Bd