How Do Planet Gears Work?

[JVN]

Originally Posted by Warren Boudreau

One of the teams last year figured out how to drive the ring and the sun (I think) with two different motors to get a constantly variable gear ratio. The CVT I think they called it. And I apologize to anyone who reads this and finds that some of the details about the CVT are distorted. It's been a rough summer and I don't remember too good sometimes.

I don't know much about planetary gears, but I do know about the "CVT" you were refferring to.

It was called the CCT - "Crazy Chicken Transmission", designed by Paul Copioli, from Team 217 - The Thunderchickens.
You can find a copy of the design, and the theory behind it here:
http://www.thunderchickens.org/downloads/cct_2002.zip

John

[Adam Y.]

Howstuffworks

[Matt Adams]

Here's a link showing planetary gear sets, along with a nice visual so you can get a better grasp on how they actually work. Very nicely done.

http://auto.howstuffworks.com/automa...nsmission2.htm

Matt

[IrisLab]

Originally Posted by JVN

It was called the CCT - "Crazy Chicken Transmission", designed by Paul Copioli, from Team 217 - The Thunderchickens.
John

This design is interesting. How well did it preform? It's very very similar to the Toyota Prius ECVT as near as I can tell. I'm not an expert in drives---not even close. I recently read an article about the Prius and how it uses a plantary gear system with an additional motor to achieve a CVT.

I noticed that the documents you listed noted that a Patent application was pending. I'd take a look at the Prius system. Maybe Toyota owes the Thunder Chickes team some big dollars! That could finance a healthy FIRST team!

The major difference that I see (and again I'm not an expert) is that Toyota uses a generator in the same way the CCT uses an extra DC motor to control drive speed and distribute torque. In the CCT the extra motor seems to have significant loss (in terms of efficiency) through the second motor. In the Prius, the generator attempts ot recover this power and feeds it back into the batteries.

Also, another diffence is that Prius uses an internal combustion engine as the main drive motor. Can we have a V-8 on a FIRST robot? :-)

Anyway, thanks for all the input. AND THE CCT IS WAY COOL! Thanks!

[matt111]

we are building a continously varible torque, velocity, steering transmission (cvt vst )
but dont ask me how it works...im just the cad dude

btw gears=not fun to model therefore use circles