Planetary Gear
*Images are attached in the doc file below
Planetary Gear
Aim – To run and simulate a planetary gear system under required conditions to study the behaviour and output characteristics of it.
Introduction – A planetary gear system is also called as epicyclic gear system , consisting of atleast 3 gears
i.e.
A sun gear
A planet gear
and A ring gear
any of the the can be input or the output depending on the design needs
Objective
1 – To create 3D models for planetary gear system with 4 planets under required constraints.
2- Obtain plot for angular velocity for each of case
1-RingGear=fixed Input=SunGear Output=CarrierGear
2-RingGear=input fixed=SunGear Output=CarrierGear
3-CarrierGear=fixed Input=SunGear Output=RingGear
3-Calculate the pitch dia and number of teeth of planet gear.
Calculations
Use the following inputs for designing the Planetary Gear
- Ring Gear
- Module = 2.5 (You must use the metric system in design modeler)
- Number of teeth = 46
- Sun Gear
- Number of teeth = 14
- Input Speed of the Gear = 200 rpm.
- Number of planet gears = 4
Ring gear dia = 2.5*46 = 115 mm
sun gear dia = 14*2.5 = 35 mm
Planet gear dia = (115-35)/2 = 40mm
planet gear teeth = 40/2.5 = 15 teeths
*module is constant for all gears in meshing
Procedure
Create a sketch to mate and to be used as reference
Using too library and metric system
import gears of required type
1 – spur gear – module2.5 dia 40 X4
2 - Spur gear – module 2.5 dia 35 X1
3 – Spur gear – module2.5 dia 115 X1
constraint these to the sketch by making them concentric to the circle in sketch and mate the front face of each gear to the front plane
using mate feature , constraint the movement of gears only along 1 axis , and also apply gear mate for them to interact as gears
CASES -
In motion analysis give motor speed at 200 rpm and fix the component according to the cases
1-RingGear=fixed Input=SunGear Output=CarrierGear
2-RingGear=input fixed=SunGear Output=CarrierGear
- 3-CarrierGear=fixed Input=SunGear Output=RingGear
Observation and discussion
- In case 1 input is sun gear and output is carrier when ring gear is fixed.
the planet gear not only rotate on their individual axis but also rolls on the ring gear.
results in low speed , but high torque - In case 2 input is ring gear and output is carrier when sin gear is fixed.
we achieve highest angular speed as higher gear messes with smallest gear
results in high speed , but low torque - In case 3 input is sun gear and output is ring when Carrier is fixed.
least angular velocity , its opposite of case 2
results in low speed , but high torque