Automatic Centrifugal 2-Speed

[Archon]

Could someone well experienced with tranmissions explain to me exactly how a 2-speed centrifugal tranny works? A picture of one such gearing is here.

It looks intriguing, but we can't figure out how the gears switch.

[sanddrag]

I was kind of wondering the same thing. I found this which may help.
http://www.rccaraction.com/articles/2_speed2.asp

I know RCCA did an arcticle just about how they work and I have every issue from the last 4 years but I don't have time to look through them all. You might try sending an e-mail to them.

[rbayer]

A google search also turned this up, although I don't know how useful/good it is: http://www.rctek.com/transmission/in...ny_design.html

[Kevin A]

i know of a CVT transmision in cars that have 2 pulleys, and on is spring loaged to expand, the other is spring loaded to contract, with a centrifuagal expander on the contracting pulley. So it changes ratios as it spins faster.

Kevin Antaki
Team 481

AIM: xpalendocious

[Al Skierkiewicz]

Archon,
Two speed transmissions are pretty common and have been used for some time. I became familiar with them on my washer a long time ago. Although the one you refer to appears to change gear ratio when the output shaft gets above a certain speed, my washer used the speed change on the input shaft to engage a centrifugal clutch to switch between agitate and spin. Centrifugal clutches had been used on garden tractors and tillers. When the engine RPM is below a certain point the engine shaft is disengaged from the output. Raise the engine RPM and internal weights force the clutch plates out and engage the engine shaft. (see the animation in Sanddrag's post.) In the first reference, I think the centrifugal part is the larger pulley on the left.

[sburro]

just want to reerect this post. Can anyone explain better or know where I can get my hands on one?

[SpaceOsc]

Originally Posted by sburro

just want to reerect this post. Can anyone explain better or know where I can get my hands on one?

Building it seems to be more a FIRST approach to it

[team222badbrad]

Here is a part break down of the transmission in my rc monster truck. The 2 speed in my truck is interal and is not outside like most rc cars. This is mainly because they need to stay clean...

I am not sure how you could make one to work because they are very high speed. I believe the engine in my rc car spins at around 50,000 RPM!


2 speed

My Tmaxx truck

I am not sure if this will help you or not but this will give you a better understanding of how a 2 speed forward/reverse nitro transmission works.

There is also a 2 speed Emaxx truck that uses a servo to shift between gears I have never accually look at one but that might be something you want to look at! http://www.traxxas.com/products/elec...s-exploded.pdf

[team222badbrad]

You can get one from tower hobbies $30 You may be able to find them cheaper if you look hard enough. You may also be able to buy one at a local hobby shop!

http://www2.towerhobbies.com/cgi-bin...?&I=LXDVA9&P=0