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Discussion Starter · #1 ·
Coming over from the Corrado group b/c I have a question for yall...
Does anyone know how this new chain driven CVT actually works? Ive read 20 or so articles so far, even the SAE article
http://www.sae.org/automag/techbriefs_01-00/03.htm
with Reinhard Gesenhaus, Audi's Manager of Transmission Engineering, explaining it, but Im still missing something. Then I pulled the patents LuK has for the CVT and the drive chain, but it seems like it would need so much clamping force it wouldnt be very efficient...
How is the chain actually able to clamp to the variator plates and transfer power from the engine? If you look at the chain closely it has tapered pins that stick out of the side of it 1/4" or so - do these pins hook up with radial grooves on the variator plates? But if so, how would the chain be able to rotate around a varying radius - the chain pins look like they are a fixed distant apart from one another and as the chain rides farther from the center of the pulley the radial grooves would become too far apart for the chain pins to ride in so the whole thing would jam...
Im lost over here...maybe its more simple and the variator plates just squeeze the sides of the chain hard enough to grip it, but it seems like it would slip - two polished metal sufaces submergerd in ATF?. And why the protruding pins on the chain then?? Why not just build a trapazoidal chain (shaped like a v-belt) so at least you have more surface area to grip.
Anyone?
Paul
92 SLC



[Modified by A2T, 7:39 AM 11-29-2001]
 

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Re: How Does CVT Actually Work?? (A2T)

Well, it's not really complicated at all. You turn the key, put it in drive and you're moving. Sorry, I don't have a clue and my brain started to hurt while reading your post.
 

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Re: How Does CVT Actually Work?? (A2T)

The articles in the most current auto mags explain it very well and even comment on the clamping force theory. See R&T and AW A4 report.
 

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Discussion Starter · #4 ·
Re: How Does CVT Actually Work?? (NC-GTI)

Thanks - I read those articles. I guess I understand it. The metal chain pins get squeezed by the conical plates on both sides, and the normal force produces enough friction to grip the pins. Seems like there would be a better way, but whatever...
I did some hand calculations and came up with about 1000 lbs clamping force, but it may even be higher than that. Crazy that so much force doesnt just bind up the running chain - esp when it tries to change ratios...or make it so inefficient (friction) its not worth it. Apparently LuK did some serious thinking on this and figured it all out. Maybe the ATF is the secret?
Paul
92 SLC
 
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