DESIGN AND STUDY OF PLANETARY GEAR ASSEMBLY

AIM

1. To study the behaviour of the motion analysis of planetary gear model using solid works for different cases which are mention below

Sl.No	Input	Output	Fixed
1	Sun Gear	Carrier	Ring Gear
2	Ring Gear	Carrier	Sun Gear
3	Sun Gear	Ring Gear	Carrier

2. To plot the angular velocity for the above cases.
3. To calculate the pitch circle diameter and the number of teeth for the planet gear.

GIVEN

1. ring gear-

Module = 2.5 (Use the metric system)

Number of teeth = 46

2. sun gear

Number of teeth = 14

3. input speed for the gear = 200 rpm
4. Number of planet gears = 4

EQUATION USED

1. Module,

`M = D/T`

BODY OF CONTENT

Planetary Gearbox

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).

The planetary gearbox got its name because of how the different gears move together. In a planetary gearbox we see a sun (solar) gear, ring (satellite) gear and two or more planet gears.

There is various application of the planetary gear

• In a robot to increase the torque
• In a printing press to reduce the speed of the rollers
• For precise positioning
• In a packaging machine for a reproducible product

CALCULATION

Calculation of teeth in the planet gear

Teeth on the ring gear = twice of teeth on the planet gear + teeth on the sun gear

46 = 2.T_p + 14

46-14 = 2.T_p

T_p = 16

Fig : 2D arrangement of the planetary gear

Where,

D_r = Diameter of the ring gear

R_s = Radius of the sun gear

D_p = Diameter of the planetary gear

`m= D/T`

For sun gear,

D_s = m.T

D_s = 2.5 x 14

D_s = 35 mm

For ring gear,

D_r = m.T

D_r = 2.5 x 46

D_r = 115 mm

For planet gear,

D_P = m.T

D_P = 2.5 x 16

D_P = 40 mm

Center distance between sun gear and the planet gear = radius of sun gear + radius of planet gear

= 17.5 + 20

Center distance between sun gear and the planet gear = 37.5 mm

Component used

Component	Unit
Sun Gear	1
Ring Gear	1
Carrier	1
Planetary Gears	4

STEPS FOR DESIGNING PLANETARY GEAR

1. Firstly, design the carrier part of the planetary gear
2. center distance between planet gear and sun gear is 37.5, so same dimension should be used in designing of the carrier part.

3. after drawing sketch which is shown in above fig go to extrude option and give proper extrude dimension. I have used 20 mm.

4. Select the one face for the making shaft as shown in figure and provide extrusion for 80mm.

5. Select another face for making 4 circle and give extrusion of 20mm which makes cylindrical part over which planet gears are mounted as shown in figure.

6. The final design for the carrier is shown in figure below

7. For creating gear from Toolbox

Go to design library - Toolbox - ANSI metric - Power transmission - gears

8. Choose spur gear for sun gear and planet gear. And choose internal spur gear for ring gear as per required quantity.

10. Give the proper color or defined the material which you want. Here I am giving color to carrier only.

11. Proper mate is done in order to achieve motion in each and every part from gear to carrier. The mate which I have done are shown in the figure below

12. Go to motion study and choose the motion analysis for doing analysis which is present at the left hand side. After that provide solid body contact and select all the component used as shown in figure below.

13. Provide motor for input of 200 rpm and plot the angular velocity of the output component for different cases. Make sure for better performance use 200 frame per second.

RESULT

Case 1- By fixing Ring gear

Input from sun gear

Output from carrier

Rpm is 200rpm

Angular velocity of carrier

Case 2- By fixing sun gear

Input from ring gear

Output from carrier

Rpm is 200rpm

Angular velocity of carrier

Case 3- By fixing carrier

Input from sun gear

Output from ring gear

Rpm is 200rpm

Angular velocity of ring gear

CONCLUSION

In Case 1 : Here we can see that the initial angular velocity is zero and when the motor starts rotating the angular velocity increases according to time.

In Case 2 : As plot defines the angular velocity is zero at the initial stage and motor start rotating the angular velocity increases drastically. Here fluctuation is induced with time.

In Case 3 : The carrier is fixed, so the planet gears is not able to revolve around the sun gear. Plot define angular velocity is zero at starting and increases drastically.

YOUTUBE LINK

Case 1- By fixing Ring gear

Case 2- By fixing sun gear

Case 3- By fixing carrier

GOOGLE DRIVE LINK

https://drive.google.com/drive/folders/1cEDN39kMvTt5t_VE0VKH_GsuUKgdkCjG?usp=sharing

REFRENCES

1. skill lync video lecture

NOTE: May be color shown in the fig is not same because of inbuilt librabry Gear is used.