Radial and tangential forces in epicyclic gears

[gsalih]

I have a query regarding tangential and radial (separating) forces present in an epicyclic gear train.
I seem to understand that the radial forces cancel each other out at the ring / planet and planet / sun interface. But do the tangential forces also cancel each other out? although i understand that tangential force transfers torque between mating gears.

[PinkertonD]

The Torque is transferred via the Sun, Planet-carrier and the ring. The method of calculating the torque-load is not a trivial issue. A job best left to software if you can find some. Maybe look for some online epicyclic gear calculators.

I have read of energy conservation methods that yield usable results with less calculations, but I have never used that approach so I cannot say if they are practical or just a whimsical Academic theory. I fear the latter.

[zeke]

"But do the tangential forces also cancel each other out? although i understand that tangential force transfers torque between mating gears. "

Take a free body diagram of a single planetary gear and you will find that the tangential forces from the ring and the sun are equal and in the same direction on the planet gear and the force through the center of the planet is twice that force.

[PinkertonD]

equal and in the same direction on the planet gear and the force through the center of the planet is twice that force.

Jeeze, Zeke, you are making it too easy for gsalih. I suspect this is a homework question as asking if tangential forces cancel out would also mean that torque does too. Not a question I would expect from someone already an Engineer.

Without torque increase/decrease, who needs a gearbox?

[gsalih]

PinkertonD, I have actually found the answer i was looking for in the following link under planetary gear section. The tangential and radial forces cancel.
I would recommend that you read this article, and please understand the question before you make comments like that.

http://suncam.s3-website-us-east-1.a...npdocs/105.pdf

[jboggs]

gsalih,
You should understand that very many students log on to this website and try to get answers to their homework. Most know that is against the policies here, so they try to hide the fact that their question is homework. Those of us who have been around a few years get a feeling that makes us suspect certain questions as homework. One of the indicators to us is when the question seems just a little too neat, tidy, and theoretical, often without any solid connections to a real world problem. In PinkertonD's defense, I too suspected that your question might be homework. He did not mean offense to you. He was just reacting to what he saw in the screen in front of him.

[PinkertonD]

Exactly JB.