Planetary Gear

Aim: To Design and Simulate a Planetary gear

Introduction & Theory: A planetary Gear is a setup of three types of gears where the center gear is known as the Sun gear, the intermediate gear/gears are known as planetary gears and the outer ring gear is known as the Internal gear. The mechanish used to hold the planatary gears in position is known as the carrier.

This type of setup is prefferable at places where there is a constrain in space and a large amount of torque or speed reduction/amplification is required.

The general layout of the Planatary gear can bee seen as:

Here the motion is either provided from the power source to the sun gear and the output is obtained at the internal gear or vice versa.

Inputs:

Module(m)

`m=2.5`

Denoting the number of teeth with term 'z'

The data for Ring Gear/Internal Gear:

Number of Teeth

`z(RG)=46`

The data for sun Gear:

Number of Teeth

`z(SG)=14`

Data for Planatary Gear:

Number of Planatary gear(n):

`n=4`

Input Speed of the Gear=200

Calculation:To design the planetary gear we will require the number of teeth(PT) on the Planetary Gear. For this we will use the formula.

`z(RG)=2*z(PG)+z(SG)`

Thus using the formula we can calculate the number of teeth on the Planetary Gear as 16

Therefore,

`PT=16`

Also the pitch circle diameter of all the gears are as:

`d=m*z`

Therefore,

`d(PG)=2.5*16=40`

`d(SG)=2.5*14=35`

`d(RG)=2.5*46=115`

Procedures: Using these data we can proceed for the modeling of our gear setup.

The cad models generated are attached and the screen shots of these models can be seen below.

Motion Study:

Case 1:

In case one the input of 200RPM is provided to the sun gear and the output is recorded on the carrier keeping the ring gear fixed.

As the ring gear is fixed the force transmited from the sun gear to the planatry gears leads to the rotaion of the carrier in relation to ring gear.

Thus the output is acheived on the carrier as it rotates.

The animated video of the same can be seen below:

Also the angular velocity of the carrier can be seen in the plot:

Case 2:

In this case the input of 200 rpm is provided to the ring gear keeping the sun gear fixed and the output is acheived from the carrier by rotating it.

The ring gear transmits the power to the planatary gears and the sun gear being restricted from revolving the carrier revolves with repect to the sun gear and the output is thus acheived on the carrier.

The animated video for the same can be seen below:

Also the plot of angular velocity of carrier with respect to time can be seen below:

Case 3:

In this case the input of 200RPM is provided to the sun gear and the output is recorded on the ring gear keeping the carrier gear fixed.As we provide the input input to the sun gear it transmits the power to the planatary gears. The carrier being fixed the planatary geras trnamits the power to the ring gear and as a result of which the ring gears revolves and the output can be recorded on it.

The animmated video of the same can be seen below:

Also the angular velocity of the rear ring with respect to the time is as:

Report on Motion analysis:

1. Firstly with the data provided we need to generate the gears in the assembly using the metric form of units nad define the number of teeth and modules for all the three gears
2. Then we need to draw the pitch circle diameters for all the three gears and make them in the proper dimmensional manner so thet we can constrain them.
3. Further we need to provide them with mates other then that of gear mates as directed in the assignment.
4. So we can use the concentric mates to acheive that.
5. Further to get the out put in the three cases we need to manuplate the mates in some cases.
6. Then after giving the motor inputs and the contacts we can run the calulations to run the motion study.
7. We can use contact sets to assign the contacts.
8. Further once the calculation is done we can go to the plot and result icon and select the parameters for which we need to display the plots in our case it is angular velocity.
9. And we can repeat the steps for the remaining two cases.