Planetary Gear
Objective: To run the motion analysis on the planetary gear with a sun gear, a ring gear, a carrier and four planet gears.
Modelling:
The following inputs are used for designing the Planetary Gear
- 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
- The module is the same for all the gears.
Ring Gear:
The ring gear is imported from solidworks toolbox and required properties have been assigned as shown below.
Sun Gear:
The sun gear is imported from solidworks toolbox and required properties have been assigned as shown below.
Planet Gear:
Calculation for number of teeth in planet gear:
Pitch circle diameter of the ring gear = Module*Number of teeth = 2.5*46 = 115mm
Pitch circle diameter of the sun gear = Module*Number of teeth = 2.5*14 = 35mm
Pitch circle diameter of the planet gear = (Pitch circle dia. of ring gear - Pitch circle dia. sun gear)/2 = 40mm
Number of teeth of planet gear = Pitch circle diameter of planet gear/module = 40/2.5 = 16
The Planet gear is imported from solidworks toolbox and required properties have been assigned as shown below.
Carrier:
The carrier is designed in solidworks as required in planetary gear mechanism as shown below.
Assembly:
All the parts are assembled to get the desired motion as shown below.
Simulation:
The simulation of planetary gear assembly will be carried out in 3 different types of scenarios as given below.
| Sl.No | Input | Output | Fixed |
| 1 | Sun Gear | Carrier | Ring Gear |
| 2 | Ring Gear | Carrier | Sun Gear |
| 3 | Sun Gear | Ring Gear | Carrier |
A new motion study is created and motion analysis is selected.
Scenario-1:
Boundary Conditions:
A rotary motar is added to sun gear with an rpm of 200 in clockwise direction, as sun gear is the input in scenario 1.
Solid body contact is applied for all parts which will be in contact in simulation with steel(dry) as material. (Same for all scenarios)
Motion analysis frames per second is set as 1200 and precision contact is applied. (Same for all scenarios)
Ring gear is fixed.
Now the motion study is calculated for 5 seconds.
The angular velocity of carrier (output) obtained is shown below.
Scenario-2:
Boundary Conditions:
A rotary motar is added to ring gear with an rpm of 200 in clockwise direction, as ring gear is the input in scenario 2.
Sun gear is fixed.
Now the motion study is calculated for 5 seconds.
The angular velocity of carrier (output) obtained is shown below.
Scenario-3:
Boundary Conditions:
A rotary motar is added to sun gear with an rpm of 200 in clockwise direction, as sun gear is the input in scenario 3.
Carrier is fixed.
Now the motion study is calculated for 5 seconds.
The angular velocity of ring gear (output) obtained is shown below.
Conclusion:
- The highest angular velocity was obtained in scenario 2, where the sun gear was fixed, carrier was the output and ring gear was the input.
- The smoothest possible angular velocity was obtained in scenario 3, where the carrier was fixed, ring gear was the output and sun gear was the input.
- So, when the carrier is fixed the angular velocity was smooth but not constant, because the planet gears were just moving around its own axis and the highest angular velocity was obtained when the ring gear was input.