Planetary Gear

AIM: To study the motion analysis of planetary gear

Theoritical background:

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 gear systems can vary in complexity from very simple to intricate compound systems, depending on the application. 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.

Uses of planetary gear

1. In a packaging machine for a reproducible products

2. For precise positioning

3. In a printing press to reduce the speed of the rollers

4. In a robot to increase the torque

Given data:

• Ring Gear
  • Module = 2.5 (using 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

D_R - diameter of Ring gear r_R - radius of Ring gear T_R - Number of teeths on Ring gear

D_S - diameter Sun gear r_S - radius of Sun gear T_S - Number of teeths on Sun gear

D_P - diameter Planetary gear r_p - radius of Planetary gear T_P - Number of teeths on Planetary gear

m - module

D_R = m*T_R = 2.5*46 = 115mm

D_S = m*T_S = 2.5*14 = 35mm

now we can calculate the diameter of planetary gear

D_P = m*T_P = 2.5*16 = 40mm

Modelling

1 Ring Gear

2 Sun Gear

3 Planetary Gear

Planetary gear arrangement

4 Carrier part

Assembly

Angular velocities for 3 different cases are given below

w_s – Angular velocity of Sun gear w_r – Angular velocity of Ring gear w_c – Angular velocity of Carrier R -- Gear ratio

Motion Analysis:

Here we have to perform 3 cases. We have to fix the component in the assembly as per the requierment and then carry out the motion study one by one

Steps:

1. After obtaining the required assembly, go to the motion study section in the solid works window and set up the motor to 200rpm at the input gear

2. Go to the contact selection and then select the contact surfaces , after that apply the material to input and the output gear

3. Go to motion study properties and select motion analysis, after that run the study for the set time limit.

4. Export the results of angular velocity for the output gear.

Case 1:

Angular velocity of the Carrier

https://youtu.be/R_mGmQMVgLI

Case 2:

Angular velocity of the Carrier

https://youtu.be/dFKikpILdl4

Case 3:

Angular velocity of the Ring Gear

https://youtu.be/QudwZauy0ac

TABULATION:

The results of the above 3 cases are tabulated below

Observation and Conclusions:

Case 1:

The gear ratio in the first case is the reduction ratio, the output speed in less than the input speed. The Angular velocity of carrier is less than the Sun gear

Case 2:

The gear ratio in the second case is the Overdrive ratio, the output speed in more than the input speed. The Angular velocity of carrier is more than the ring gear

Case 3:

The gear ratio in the third case is the reduction ratio,but the output direction is reversed. The output speed in less than the input speed. The Angular velocity of ring gear is less than the Sun gear