Planetary Gear
DESIGN OF PLANETARY GEAR
Motion study of a Planetary Gear.A planetary gear set is made up of three types of gears; a sun gear, planet gears, and a ring gear. The sun gear is located at the center, and transmits torque to the planet gears which are typically mounted on a moveable carrier. The planet gears orbit around the sun gear and mesh with an outer ring gear.Planetary gears are often used when space and weight are an issue, but a large amount of speed reduction and torque are needed.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, in the load is more evenly distributed and therefore the gears are more resistant to damage.
Design of Gear
The number of teeth (z).
This value is: z = d/m
Module (m). Ratio between the pitch circle in millimeters and the number of teeth. The value of the module is determined by calculating the material resistance in relation to the force to be transmitted and the gear ratio.
Two mating gears must have the same module: m = d/z
Pitch Diameter (d) is the diameter of the pitch circle; its value is: d = m x z
Ring Gear
Module = 2.5 use of metric system
Number of teeth = 46
Pitch circle diameter = 115 mm
Sun Gear
Module = 2.5
Number of teeth = 14
Pitch circle diameter = 35 mm
Input Speed of the Gear = 200 rpm.
Planet Gears
Module = 2.5
Number of teeth = 16
Pitch circle diameter = 40 mm
Number of planet gears = 4
In assembly spur gears from toolbox and modify the solid geometry as requirement.
Start a motion study defining motor input to sun
Conditions for Analysis
Sl.No Input Output Fixed
1 Sun Gear Carrier Ring Gear
2 Ring Gear Carrier Sun Gear
3 Sun Gear Ring Gear Carrier
Angular velocity @ 200rpm
1200 deg/sec
Case1
We get reduced angular velocity
We get a reduction gear ratio of nearly4:1
Case2
We get reduced angular velocity
We get a reduction gear ratio of nearly 4:3
Case3
We get reduced angular velocity
We get a reduction gear ratio of nearly 10:3
https://drive.google.com/open?id=1gpYTITF9upyey2MRhAgnKSuUpB1WZjYD