Planetary Gear
Epicyclical gearing
Introduction:
An epicyclical gear train (also known as planetary gear) consists of two gears mounted so that the centre of one gear revolves around the centre of the other. A carrier connects the centres of the two gears and rotates to carry one gear, called the planet gear or planet pinion, around the other, called the sun gear or sun wheel. The planet and sun gears mesh so that their pitch circles roll without slip. A point on the pitch circle of the planet gear traces an epicycloids curve. In this simplified case, the sun gear is fixed and the planetary gear(s) roll around the sun gear.
No of component required are:
1-Ring gear
2-Sun gear
3-Planet gear
4-Carrier
|
Sl.no |
Types of gear |
module |
No of teeth |
Pressure angle(deg) |
|
1 |
Ring gear |
2.5 |
115 |
20 |
|
2 |
Sun gear |
2.5 |
35 |
20 |
|
3 |
Planet gear |
2.5 |
40 |
20 |
Creating the 3d model:
For creating 3d model go to
Design library-toolbox-ANSI metric-power transmission-gear for sun and planet chose spur gear, for ring gear chose internal spur gear.
Ring gear:
Sun gear:
Planet gear:
Carrier:
Final assembly:
Motion analysis:
Ring gear is fixed. motor –sun gear
The plot of angular velocity of ring gear v/s time.
CASE 2:
Sun gear fixed. motor –ring gear.
The plot of an angular velocity of the carrier against time.
Case 3:
Carrier fixed .motor-sun gear.
The plot of angular velocity of the ring against time.
Observation and calculation:
In first case when the input is given to sun gear and output is obtained at the carrier keeping the ring gear fixed the planet gear not only rotate about their axis but also forced to roll on the inside of the ring gear along with the carrier as the ring gear is fixed . the angular velocity obtained for the case is between 235-313 deg/sec.
In the second case when the input is given to the ring gear and output obtained from the carrier keeping the sun gear fixed. The angular velocity achieved is maximum science the internal gear is big and planet gear are small comparatitivly so when a large gear meshes with small gear the velocity achieved from the small gear is high because the velocity ratio is high.
YouTube link: https://www.youtube.com/watch?v=wVmLoxsvVCw
References :