Planetary Gear
Aim:
The main aim here is to analyze the motion of the planetary gear with various conditions and to predict the angular velocity of the components upon fixing some components.
Introduction:
An epicyclic gear train (also known as planetary gear) consists of two gears mounted so that the center of one gear revolves around the center of the other. A carrier connects the centers 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 epicycloid curve. In this simplified case, the sun gear is fixed and the planetary gear(s) roll around the sun gear.
By our model, the components are
Ring gear -1
Sun gear -1
Planets gear -4
Carrier -1
Gear parameters:
3D Models:
We don't apply gear mates in this assembly.
after assembly, we check the mate and proper engagement of the gears through Move component option under the assembly section.
Conditions:
Motion Analysis:
Contact pairs are given material property as Dry steel
there are 8 contact pairs totally:
4 contact pairs - between the sun gear and planet gears.
4 contact pairs - between Planets gears and Ring gear.
Calculations:
Ring gear: Diameter of the gear = module *Number of teeth
=2.5*46
= 115mm
Sun gear: Diameter of the gear = module*Number of teeth
=2.5*14
=35mm
Planet gear: Diameter of the gear = radius of the ring -radius of the sun gear
= (115/2) -(35/2)
= 40mm
Number of teeth:
Number of teeth = 16
Plot:
Case1: Ring gear is fixed and the input is given in Sun gear at speed of 200 rpm
Case2: Sun gear is fixed and the ring gear is given input of rotational speed 200 rpm
Case3: the carrier is fixed and the sun gear is given input of rotational speed 200 rpm
Observations:
Case 1: the input is given in the sun gear and the output is obtained through carrier gear by fixing the ring gear. The angular velocity of the carrier gear is a fluctuation between 260-290 rad/sec. A sudden rise in angular velocity is observed in the plot because of the sudden hit of the sun gear with the planet gears.
Case 2: The input is given to the ring gear and the output is obtained from the carrier gear by foxing the sun gear. The angular velocity is fluctuating between 900-950 rad /sec.
Case 3: The input gear is given to the sun gear and the output is obtained from the ring gear by fixing the carrier gear. the angular velocity is fluctuating between 350-400 rad/sec.
Youtube links for various case:
case 1: Planetary gear with Fixed ring gear