Author Topic: NSU Cam Drive  (Read 4380 times)

Offline dvbydt

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NSU Cam Drive
« on: January 22, 2012, 08:03:23 PM »
The Modders might be interested in what I have put my poor brain through to understand this drive system.
To explain, I need a compact cam drive system for my compressed air V8 engine see:-

http://www.homemodelenginemachinist.com/index.php?topic=14530.0

I had seen this system in a review of a NSU Prinz car years ago and
filed it away to look at later, because I didn't understand how it
worked. The journalists that reviewed it didn't understand either so
just described it as "Two eccentric rods"


http://cybermotorcycle.com/gallery/nsu/NSU_Ultramax_Camshaft_Drive.htm

This is an animated version :-

http://www.nsu4.nl/english/e1ultramaxcamshaftsystem.html

The third rod nearest the engine just maintains the centre distance.

So, this how I have managed to explain it to myself, if it helps
anyone else, that would be a bonus.

Firstly, locomotve wheels are phased 90 degrees on each side, it is
called quartering and allows the double acting cylinders to be self
starting. ( Pretty useful, wouldn't want to push a steam train!)

Lego model so that both sides can be seen, not easy with a full
size engine.

<a href="http://www.youtube.com/watch?v=B78NleuC0oc" target="_blank">http://www.youtube.com/watch?v=B78NleuC0oc</a>


Note that only the left side is driven. The right hand side is
made to rotate by the coupling rods.

Now I have transferred one of the rods to the other side :-

<a href="http://www.youtube.com/watch?v=B78NleuC0oc" target="_blank">http://www.youtube.com/watch?v=B78NleuC0oc</a>

Another view :-

<a href="http://www.youtube.com/watch?v=E5urzJWLE0U" target="_blank">http://www.youtube.com/watch?v=E5urzJWLE0U</a>

Again only the left side is driven.

If I can manage to machine the two 90 degree cams, I should have
a slick way of joining the crankshaft to the overhead cam without
the use of gears,belts or chains.


Ian
« Last Edit: January 22, 2012, 08:18:56 PM by Brass_Machine »

Offline Anzaniste

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Re: NSU Cam Drive
« Reply #1 on: January 22, 2012, 08:33:04 PM »
W O Bentley designed the 6.5 litre Bentley with a 3 con rod eccentric drive in 1928. It won Le Mans so it can't be too bad a system! :clap:
Scrooby, 1 mile south of Gods own County.

Offline dvbydt

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Re: NSU Cam Drive
« Reply #2 on: January 23, 2012, 04:08:32 AM »
His name came up once on my internet searches but I couldn't find a picture of his version.

Ian

Offline dvbydt

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Re: NSU Cam Drive
« Reply #3 on: February 10, 2012, 10:07:11 AM »
Well, it is possible to scale down this cam drive system.

http://youtu.be/Z4vHcDu1XfU

 The centre distance on this video is 40 mm and it is here driven by my battery drill, maximum speed shown is about 900 rpm. Using my mains drill,  it will run up to 3,000 rpm easily. So it now needs some design work to get it to fit on the end of the crankshaft. In this application it does not need a gear reduction.


Ian