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Our Prototype Ratcheting CVT

Nately27

Monkey
Jul 29, 2003
121
0
as an excerpt from the gearbox thread:
bcd said:
here is what i think wouldbe light, simple, cvt for a bike
A couple of us here, miket and others, have been working on a ratcheting CVT. Our first fully functional prototype was finished last week. It has a gear ratio from 1 to 3, and should have a completely uniform output (although we havent hooked up a DAQ system yet).

video
I would suggest turning down the volume, a bunch of guys start yellin halfway through... the input is not constant, so its tough to see the speed increase, especially from that angle.

Its still overweight and oversized for a bicycle, but at this stage it should handle 120[ft-lbs]. So we're still happy with it.
 

Nately27

Monkey
Jul 29, 2003
121
0
its an avi file, so should play in quicktime or winamp, I'm gonna try to get another video up today, with some pics too.
 

jlucas

Chimp
Jan 16, 2013
2
0
I was wondering if you have the ratcheting CVT video posted somewhere that I can access without authorization?
 

jlucas

Chimp
Jan 16, 2013
2
0
Just wondering if anything became of the ratcheting CVT project.
ZeroMax has a ratcheting CVT that they have in production, but the output is not "uniform". The fluctuating output speed of ratcheting designs tends to produce significant vibration/pulsation issues.
My first inclination, without seeing the design, is that it likewise, does NOT produce a uniform velocity output, but I was curious what the team had come up with.
 

monroe123

Chimp
Mar 15, 2011
6
0
Anyone got any idea what ever came of the IVT gearbox by Derek Lahr? To me it seemed to show a lot of promise.

EDIT- just found this;
http://scholar.lib.vt.edu/theses/available/etd-11192009-124025/unrestricted/Lahr_DF_T_2009.pdf

Hmmm, very interesting!
Not much has happened with the transmission/bike Derek built to work with it since 2009. There was a senior project the following year that was supposed to get the transmission ready for actual use (harden the design etc.) but they didn't make enough progress to use it for a go-kart like they had planned. Basically Derek is too busy building robots these days to spend the proper amount of time to get the thing working in a bike. Hopefully he gets his priorities straight and finishes it at some point.
 

Nately27

Monkey
Jul 29, 2003
121
0
Fun to see interest in the CVT. The best video is from the fellas at pinkbike.com.

All the work that was done is covered in my thesis, except that one patent was awarded, and a second is applied for. I am working on graduating, and would love to get into the bike biz. Have to see how the cards play out.