Lego CVT-IVT
Intro: Lego CVT-IVT
I have been looking at Continuously Variable Transmissions, CVT(s) and Infinitely Variable Transmission IVT(s) for a few days and decided to make myself one.
i will walk you through the key parts so you can do it too(please give constructive comments about anything in this instructable...especially about the usage of terms)
This is a plate and wheel model, basically the IVT part works by moving the wheel nearer or further from the center of the plate. The nearer a point is to the center of the plate, the slower it moves and thus turns the wheel slower but with more torque. The CVT part is the fly wheel which "contracts" along its axis when spun and thus, moving the wheel further from the center of the plate.
due to some unknown problems, i am unable to add photo notes or embed my video, please bare with me while i try and fix this problem
oh, by the way, i am in the 13-18 category.
Alright, as pointed out by fellow user jj.inc:
"Actually, just for informational purpose, this is a CVT only, not an IVT. An IVT can output at such a low gear that there is no output at all. A ∞:0 ratio is not possible with this device, so it is a CVT which from ratio A:X to ratio B:X where X ≠ 0 can have infinite variance."
learn more about CVT and IVT by just google-ing it
http://en.wikipedia.org/wiki/Continuously_variable_transmission
http://auto.howstuffworks.com/cvt.htm
STEP 1: Plate and Wheel Assembly
Just attach a CD or any disc you are willing to sacrifice to the Lego parts ensuring that the lego axis is dead center.
i use wheels with tires to get a good grip on the CD, it might be better to make holes in the CD for the Legos to attach better
next you would want to get a wheel with its tire as the driven wheel, make sure you use one with good grip, the bigger the wheel you use(diameter) the slower it goes, but with more torque
i use wheels with tires to get a good grip on the CD, it might be better to make holes in the CD for the Legos to attach better
next you would want to get a wheel with its tire as the driven wheel, make sure you use one with good grip, the bigger the wheel you use(diameter) the slower it goes, but with more torque
STEP 2: Flywheel Assembly
Here you would want the output shaft to be stationary while the shaft connected to the plate and wheel assembly to be able to slide in and out. The flywheel uses 3 axis on each side to make it able to "contract" when centripetal forces move the middle axis out.
Remember to add a rubber-band or two or the flywheel might not return to its default configuration, selecting the rubber band requires some trial and error as there are many variables.
Remember to add a rubber-band or two or the flywheel might not return to its default configuration, selecting the rubber band requires some trial and error as there are many variables.
STEP 3: Powering the Unit
Since 99% of this project is made of Lego, i would use Lego to power it.
here i used two 5000rpm lego motors with very very low torque, so i geared it down a little (1:3 i think)
but feel free to use anything you like
here i used two 5000rpm lego motors with very very low torque, so i geared it down a little (1:3 i think)
but feel free to use anything you like
STEP 4: Some Extra Photos
a few photos of the project
STEP 5: A VIDEO of It Working!!
here is a video of my CVT-IVT in action
23 Comments
tpace3 7 years ago
Does anyone have any idea of how to make a gear that would work like the disc in this case?
michaelgohjs 7 years ago
Here is something i came up with that might interest you
https://www.instructables.com/id/Continuous-mesh-Positively-engaging-CVT/
rsnyder8 10 years ago
Very nice
insmac 11 years ago
One note: When writing documentation you should never assume all readers will know what your acronyms mean. So, it is common, the first time it is used, to define all acronyms or jargon thus: CVT (constant velocity transmission).
In many cases you may even include a link to, for instance, a WIKI page where it is defined in more detail.
michaelgohjs 11 years ago
stringstretcher 11 years ago
Cool project.
michaelgohjs 11 years ago
the balancing wheel does not affect the function of device its there to...well balance it
kmcdowell4 11 years ago
RSV26 11 years ago
michaelgohjs 11 years ago
RSV26 11 years ago
CrashMGD 11 years ago
RSV26 11 years ago
jj.inc 12 years ago
michaelgohjs 12 years ago
Thanks for the info (^.^)
jj.inc 12 years ago
jj.inc 12 years ago
Dr_Stupid 12 years ago
michaelgohjs 12 years ago
hmm.. never really thought of it as a teaching aid, but i think its kind of suitable since students would be able to see, hear and feel the system at work
isalas 12 years ago