Thanks to Ole Kirk Christiansen's disturbingly compelling TechnicBRICKs blog, I now know that a Lego automatic transmission can be surprisingly simple.
I've seen outrageously bulky and complex variable-ratio Lego transmissions before, but this one...
...is pretty much pocket-sized.
It's actually a continuously variable transmission (based on differentials rather than the belts often found in full-scale designs), not a conventional auto with a small integer number of ratios.
But don't worry, there are plenty of separate-ratio autos, too:
Check out the TechnicBRICKs post for more videos and pointers to further info.
29 December 2007 at 7:15 pm
I prefer the Lego limited-slip differentials. It's just an idea that seems like it would lend itself to Lego very nicely, but of course, it doesn't, as they're engineered to such insane tolerances and use parts that Lego hasn't seen fit to produce. Some of the contortions that are gone through in order to reproduce something that a Lego car would have no worries about (power transfer to compensate for loss of traction) are interesting all by themselves.
29 December 2007 at 7:16 pm
http://www.bloomington.in.us/~alano/brian/torsen/
Oops.
30 December 2007 at 2:32 am
How about http://home.online.no/~selode/lego/limited.html for a limited slip diff? Not the ideal solution, but very small and simple.
I'm exactly the kind of nut who designs stuff like this in his spare time. I've been working on my own automatic transmission without the use of mindstorm parts for awhile now. Getting there...