Planetary Gear
Aim: To run a simulation on the following cases, with data provided below to obtain the planetary motion.
| Sl.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.
You should not use the Gear Mate.
The module is the same for all the gears.
You need to calculate the pitch circle diameter and the number of teeth for the planet gear.
Data Given:
Ring Gear
Module = 2.5 (You 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
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 (yellow), and transmits torque to the planet gears (blue) which are typically mounted on a moveable carrier (green). The planet gears orbit around the sun gear and mesh with an outer ring gear (pink). 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.
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, in the load is more evenly distributed and therefore the gears are more resistant to damage.
Calculations:
m = d/N
m = Module of gear
d = pitch diameter
N = No. of Teeth
Ring Gear:
Module = 2.5
No. of Teeth = 46
The pitch diameter of gear = 46*2.5 = 115 mm
Sun Gear:
Module = 2.5
No. of Teeth = 14
The pitch diameter of gear = 14*2.5 = 35 mm
Planetary Gear:
Module = 2.5
(diameter of ring gear) = (diameter of sun gear)+ (diameter of planetary gear)*2
115 = 35 + (diameter of planetary gear)*2
(diameter of planetary gear)*2 = 80
(diameter of planetary gear) = 40
No. of Teeth = 16
All units assumed in mm.
| Gear Type | Module | Pitch Diameter | No. of Teeth |
| Ring | 2.5 | 115 | 46 |
| Sun | 2.5 | 35 | 14 |
| Planetary | 2.5 | 40 | 16 |
Configuration for the Gears:
Ring Gear:
Sun Gear:
Planetary Gear:
Carrier:
Motion Study Setup:
For all the cases in the motion study, the following body contacts are given and change is made to the rotor position with 200 RPM for all the rotors.
After completing these steps we calculate the results and then use the plot option to plot all the necessary graphs.
Plots:
Case 1: when the ring gear is fixed, we calculate the angular velocity for input at sun gear and output at carrier gear.
INPUT
Here, we can observe that as we had set the rotor to rotate at a constant speed of 200 RPM so, the angular velocity of sun gear also remains the same throughout the simulation.
OUTPUT
In this case, there is a rise in the angular velocity from a minimum value of zero because there is power transmission from the gears to the carrier.
Case 2: When the sun gear is fixed, we calculate the angular velocity for input at ring gear and output at carrier gear.
INPUT
Here, we can observe that as we had set the rotor to rotate at a constant speed of 200 RPM so, the angular velocity of the ring gear also remains the same throughout the simulation.
OUTPUT
In this case, there is a rise in the angular velocity from a minimum value of zero because there is power transmission from the gears to the carrier.
Case 3: when the carrier gear is fixed, we calculate the angular velocity for input at sun gear and output at the ring gear.
INPUT
Here, we can observe that as we had set the rotor to rotate at a constant speed of 200 RPM so, the angular velocity of the sun gear also remains the same throughout the simulation.
OUTPUT
In this case, there is a rise in the angular velocity from a minimum value of zero because there is power transmission from the gears to the ring gear.
Animation:
Assembly for the fixed ring gear
https://www.youtube.com/watch?v=kHjC2LXChP4
Assembly for the fixed sun gear
https://www.youtube.com/watch?v=9sLvzofeJdQ
Assembly for the fixed carrier
https://www.youtube.com/watch?v=5kcODohvRSc
Conclusion:
The simulation for all the three cases is successfully run and their plots are generated as shown above.
CAD Files:
https://drive.google.com/drive/folders/1jclBuxM-ayVN2HjQ9JsgmxEOIRs7Gs8M?usp=sharing
References:
https://gearmotions.com/fundamentals-planetary-gear-systems/