- #1
mrhall1923
So I've found the following formula for calculating the gear ratio of a planetary gear.
Tr Turns of the ring gear
Ts Turns of the sun gear
Ty Turns of the planetary gear carrier
R Ring gear teeth
S Sun gear teeth
P Planet gear teeth
( R + S ) ×Ty = R × Tr + Ts × S
The example I saw on the same website used a fixed ring gear so Tr=0 and the formula worked great.
My question is about having a fixed planetary gear carrier (Ty) with the ring gear being the input and the sun gear being the output. If Ty=0 in the above formula, then the left side of that equation will always be 0 and I'm at a loss at how to solve for Ts.
I have a feeling that there is a better formula for solving this. Can someone help?
Next,
I'm trying to design a 2 stage planetary gearbox with the following.
First planetary gear:
Planetary gear carrier = input
Ring gear = fixed
Sun gear = output (to second planetary gear)
Second planetary gear:
Planetary gear carrier = fixed
Ring gear = input (from first planetary gear)
Sun gear = output
Can anyone provide a single formula for solving the overall gear ratio? So one turn of the first planetary gear carrier will provide how many turns of the second sun gear? I'm looking for a formula that I can use for different size gears of varying tooth quantities.
Tr Turns of the ring gear
Ts Turns of the sun gear
Ty Turns of the planetary gear carrier
R Ring gear teeth
S Sun gear teeth
P Planet gear teeth
( R + S ) ×Ty = R × Tr + Ts × S
The example I saw on the same website used a fixed ring gear so Tr=0 and the formula worked great.
My question is about having a fixed planetary gear carrier (Ty) with the ring gear being the input and the sun gear being the output. If Ty=0 in the above formula, then the left side of that equation will always be 0 and I'm at a loss at how to solve for Ts.
I have a feeling that there is a better formula for solving this. Can someone help?
Next,
I'm trying to design a 2 stage planetary gearbox with the following.
First planetary gear:
Planetary gear carrier = input
Ring gear = fixed
Sun gear = output (to second planetary gear)
Second planetary gear:
Planetary gear carrier = fixed
Ring gear = input (from first planetary gear)
Sun gear = output
Can anyone provide a single formula for solving the overall gear ratio? So one turn of the first planetary gear carrier will provide how many turns of the second sun gear? I'm looking for a formula that I can use for different size gears of varying tooth quantities.