If you can make the travel long enough they can be made to isolate the driveline from TVs down to 80 Hz, but this is tricky. Another approach is to use a dual mass flywheel which allows you to put a low pass filter into the system.
Strictly speaking they detune the system - springs can't 'absorb' energy, as such, although they can certainly reduce the amplitudes of modes.
GregLocock,
What's a TV; and, what's a dual-mass flywheel and a low-pass filer, and how is it inserted into the driveline? Are we talking mechanical driveliness here?
Terr
TV=torsional vibration, a low pass filter is a filter that removes high frequencies, a dual mass flywheel is one in which there are two flywheel discs, separated by a compliant system of some form (rubber would be good), which forms a low pass filter for rotational vibrations, and yes we are talking mechanical drivelines.
Thanks for the education. I had been thinking I'd have to go to an expensive full-phase double cage sprag.
Eighty Hz is still 2400 pulses per minute....
1. I'm working with an 8-cyl 4-cycle input,and the idle speed about 600-rpm... that's 2400... so how do I figure how much spring I need? Or if that's too critical, can I buy a dual mass flywheel somewhere? (351-cu.in)
2. I'm also working on a problem with a 28-cyl 4-cycle engine, and wondered if it can be detuned with a simple spring plate. It drives through a 6-in. dia shaft, to a contra-rotating dual 4-blade prop, reduced to .381. Would it need a dual mass flywheel too, or could a spring plate detune it?
1 I don't know how to calculate it, we use suck it and see to tune spring rates. You should be able to buy a dual mass flywheel, I imagine Cadillac use them, even Corvette might.
2 Oh just the 28 cylinders is it? Sorry, way out of my experience, but given that you are talking about an expensive installation I would call in an expert. In England I'd talk to Holzer (spelling?).
Cheers
Greg,thanks for the info. I'll check out the Caddy and the 'Vette parts. Regarding the 28-cyl., that's for a fiction story I'm trying to write... about a WW II aircraft project. I just wanted to avoid saying anything really dumb... but maybe that's a lost cause.
Thaks again. T.
On Corvettes the Lotus-designed (and Mercury Marine-built) LT-5 engine used in the ZR-1 had a dual-mass flywheel behind the ZF 6-speed.
Big drawback was of course the hugely increased mass of the flywheel, unacceptable to some sporting types!
