MOTION ANALYSIS OF PLANETARY GEARS
Aim:
To Construct a Planetary gear system with four planet gears with a carrier and to analyze the angular velocities for different cases.
Introduction:
Planetary Gear System or an epicyclic gear train is used to set different gear ratios by using three sets of the gears sun gear, planet gear, and ring gear.
All the planet gears are mounted to a single rotating member, called a cage, arm, or carrier where the output is obtained.
A planetary gear set is comprised of an outer gear ring that's called the ring gear. As they rotate inside of the ring gear, the planetary gears create pitch circles that can be formed into a gear train that, in turn, is hooked up to input and output shafts.
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, the load is more evenly distributed, and therefore the gears are more resistant to damage.
Software Used:
Solidworks
Formula Used:
To calculate the parameters of Sun Gear,RING Gear and Planet Gears ,if we have any two-parameter such as module or pitch of circle or number of teeth between the Gears, we can find the third parameter. Hence, to calculate the required parameters we are using the following formula.
Module = Pitch Circle Diameter/ Number of teeth
[m=dT]">
Where,
m = module
[The module is also known as Addendum which is the ratio of reference diameter (or) Pitch diameter to the number of teeth. a module is the unit of size that indicates how big or small a gear is.]
d = pitch diameter
[Pitch diameter is a diameter of the pitch circle.]
T = number of teeth
Procedure:
The Module of all the gears in mesh with each other needs to be same for the law of gearing to be satisfied.
Input Speed of the Gear = 200 rpm(As given in the challenge)
1.Conditions:
2.Ring Gear:
Module = 2.5 mm Number of teeth = 46
Number of teeth = 46
Face Width= 10 mm
Pitch Circle Diameter = 46*2.5 = 115 mm
3.Sun Gear:
Module = 2.5 mm
Number of teeth = 14
Face Width= 10 mm
Sun Gear Pitch Circle Diameter = 14*2.5 = 35
4.Planet Gear:
Module = 2.5 mm
Number of planet gears = 4
Number of teeth in Planetary Gear = 40/2.5 = 16
Face Width= 10 mm
Pitch Circle Diameter=40 mm
5.Carrier:
6.Assembly:
Output:
1.Motion Analysis with Ring gear fixed and Sun gear at 200 rpm(study 1)
Link: https://youtu.be/C10gaQej0ho
2.Motion Analysis with Sun gear fixed and Ring gear at 200 rpm(study 2)
Link: https://youtu.be/mU8HrH_U7wI
3.Motion Analysis with Carrier fixed and Sun gear at 200 rpm(study 3)
Link:https://youtu.be/r9CthXVcKmQ
Component File Link: https://drive.google.com/file/d/1qZib4MJk1QpGYWsmwfG-BC9hEMIx9YCe/view?usp=sharing
(The Parts and assembly files are put into one zip file)
Conclusions:
- These planetary gears or epicyclic gears are more generally used for increasing the torque by paying the price of speed reduction in return.Thus always the output speed will be less than the input speed.
- When Sun gear is input gear, the required speed is achieved within a short duration of time. But when ring gear is input gear, the required speed is achieved linearly with time.
- The output speed has small disturbances due to collisions between the gear tooth.The power transmission could be made smooth and noiseless by employing Helical Gears instead of Spur Gears.