Planetary Gears MBD Simulation Using Solidworks.
Planetary Gears Using Solidworks
Aim:- To perform motion analysis of planetary gears and show it in graphical representation.
Theory:-
A planetary gearbox is a gearbox with the input shaft and the output shaft aligned. A planetary gearbox is used to transfer the largest torque in the most compact form (known as torque density).
In mathematical terms, the smallest reduction ratio is 3: 1, the largest is 10: 1. At a ratio of less than 3, the sun gear becomes too big against the planet gears. At a ratio greater than 10 the sun wheel becomes too small and the torque will drop. The ratios are usually absolute i.e. an integer number.
Whoever invented the planetary gearbox is not known, but was functionally described by Leonardo da Vinci in 1490 and has been used for centuries.
A planetary gear mechanism is a gear mechanism consisting of 4 components, namely, sun gear A, several planet gears B, internal gear C and carrier D that connects planet gears as seen in the graph below. It has a very complex structure rendering its design or production most difficult; it can realize the high reduction ratio through gears, however, it is a mechanism suited to a reduction mechanism that requires both small size and high performance such as transmission for automobiles.
The planetary gearbox got its name because of how the different gears move together. In a planetary gearbox we see a sun (solar) gear, satellite (ring) gear and two or more planet gears. Normally, the sun-gear is driven and thus move the planet gears locked in the planet carrier and form the output shaft. The satellite gears have a fixed position in relation to the outside world. This looks similar to our planetary solar system and that is where the name comes from. What helped was that ancient gear constructions were used extensively in astrology for mapping and following our celestial bodies. So it was not such a big step to make.
Objective:-
Motion analysis is performed to get information about angular velocity Vs Time when ring gear is fixed and sun gear is let to rotate or vice versa.
Angular Velocity Vs Time plot for Sun gear fixed and ring gear rotating.
Dimensions of Gears:-
Ring Gear:-
Module:- 2.5
Number of teeth= 46
Pitch Diameter=2.5*46=115mm
Sun Gear:-
Module:- 2.5
Number of Gear=14
Pitch diameter=2.5*14=35mm
Planetary Gear:-
Module:- 2.5
Number of Gear=16
Pitch diameter=2.5*16=40mm
Different Parts:-
Ring Gear
Sun Gear:-
Planetary Gear:-
Carrier:-
Assembly:-
Plots:-
Ring Gear:- Motor
Sun Gear:- Fixed
Carrier and Planetary Gear:- Rotating
In this plot as we fix sun gear the plot becomes unstable
Ring Gear:- Fixed
Sun Gear:- Motor
Planetary Gear & Carrier:- Rotating
In this plot as we fix ring gear the plot becomes unstable
Ring Gear & Planetary Gear:- Rotating
Carrier:- Fixed
Sun gear:- Motor
In this plot as we fix carrier the angular velocity of Ring gear and planetary gear increase suddenly and remains stable.
Conclusion:-
It can be concluded that as we fix carrier the plot becomes stable whereas when we fix ring gear or sun gear the graph becomes unstable.