Planetary Gear
PLANETARY GEAR
GEARS
A gear or cog is a rotating machine part having cut teeth or, in the case of a cogwheel, inserted teeth (called cogs), which mesh with another toothed part to transmit torque. Geared devices can change the speed, torque, and direction of a power source. Gears almost always produce a change in torque, creating a mechanical advantage, through their gear ratio, and thus may be considered a simple machine. The teeth on the two meshing gears all have the same shape. Two or more meshing gears, working in a sequence, are called a gear grain or a transmission. A gear can mesh with a linear toothed part, called a rack, producing translation instead of rotation.
GEAR TERMINOLOGY
Basic Gear Terminology Face Width is the length of the teeth in the axial direction. Outside Diameter (O.D.) is the diameter of a circle around the outer surface, or tops of the gear teeth. Pitch Diameter (P.D.) is the diameter of the pitch circle.
PLANETARY GEAR
Planetary gear train consists of a sun gear, planet gears supported by the carrier and a ring gear
OBJECTIVE:
Following inputs are used for designing the Planetary Gear. (using the metric system)
Ring Gear
- Module = 2.5
- Number of teeth = 46
Sun Gear
- Number of teeth = 14
- Number of planet gears = 4
Input Speed of the Gear = 2000 rpm.
The dimensions of the carrier depend on the shaft diameter of the planet gear.
With the above input parameters, you are going to run a simulation on the following cases,
|
Input |
Output |
Fixed |
|
Sun Gear |
Carrier |
Ring Gear |
|
Ring Gear |
Carrier |
Sun Gear |
|
Sun Gear |
Ring Gear |
Carrier |
Hint:
Input- Rotary Motion given to that part as input.
Fixed-Make that particular component as a fixed part.
Output- After motion analysis, Angular Velocity of that part is plotted as a graph.
PROCEDURE:
Formula used:
M = d / T
Where,
M = Module
d = Pitch Diameter of the Gear
T = Number of Teeth
Sun Gear Calculation:
Module, M = 2.5
Number of Teeth, T = 14
d = 2.5*14
d = 35
Ring Gear Calculation:
Module, M = 2.5
Number of Teeth, T = 46
d = 2.5*46
d = 115
Planet Gear Calculation:
In this case, we need to find both Pitch Diameter of the Planet gear (d) as well as the Number of Teeth (T). Hence we cannot apply the above formula for calculation. Instead we can use the formula given below:
Radius of ring gear = Radius of sun gear + Radius of planetary gear
From this we obtain the diameter and we know the module is same for all gears the number of teeth can be obtained from the following formula
T = d / M
On substituting the known values, we get the Number of teeth for the planetary gear as 16.
|
|
MODULE |
NUMBER OF TEETH |
PITCH DIAMETER OF GEAR |
|
Ring Gear |
2.5 |
46 |
115 |
|
Sun Gear |
2.5 |
14 |
35 |
|
Planetary Gear |
2.5 |
16 |
40 |
DESIGN AND ASSEMBLY FILES
Ring gear
Module = 2.5
Pitch Diameter of Gear = 115
Number of teeth = 46
Pressure angle = 20 degree
Face width = 10
Outside diameter = 130
Sun Gear:
Module = 2.5
Pitch Diameter of Gear = 35
Number of teeth = 14
Pressure angle = 20 degree
Face width = 10
Planetary Gear:
Module = 2.5
Pitch Diameter of Gear = 40
Number of teeth = 16
Pressure angle = 20 degree
Face width = 10
ASSEMBLY
MOTION STUDY ANALYSIS:
CONDITION 1
INPUT - SUN GEAR
OUTPUT - CARRIER
FIXED -RING GEAR
CONDITION 2
INPUT - SUN GEAR
OUTPUT - CARRIER
FIXED -RING GEAR
Condition 3
INPUT - RING GEAR
OUTPUT - CARRIER
FIXED -RING GEAR
https://drive.google.com/drive/folders/1J5yFaiJU7pC_1KBkAm00SFNg6MxDxhNX?usp=sharingRESULT:
Thus the Planetary gear is been designed and stimulated the motion analysis by using the Multibody Dynamics in Solidworks
https://www.youtube.com/watch?v=bAtG3g4Ln0I&feature=youtu.be
https://www.youtube.com/watch?v=oUyLxyCuIEE&feature=youtu.be
https://www.youtube.com/watch?v=so70jUpiuls&feature=youtu.be