carcentric
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| posted on 2/3/04 at 03:43 AM |
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Maximum angle of propshaft u-joints
What's the maximum angle a propshaft can be run at without irritating vibration?
Would something in the 6.9-7.9 degree range be okay?
Assumptions: trans output and differential pinion are parallel, u-joints are in phase, speeds up to 70 mph, driveshaft mass is small (solid shaft
about 3/4" in diameter).
This is the plan for a shaft made up of two Honda CX500 shafts welded rear to rear (for a trike I'm building):
M D "Doc" Nugent
http://www.carcentric.com
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Alan B
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| posted on 2/3/04 at 05:39 PM |
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I would not have thought that the angle shown was excessive at all IMO....
Love to hear some more informed opinions though.
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Mark Allanson
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| posted on 2/3/04 at 08:40 PM |
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When I was researching propshafts, I came accross a site with a table of prop angles to safe RPM's, the greater the angle, the less RPM is safe
(no sh1t sherlock!!)
I cannot remember the site, but it was one of the main manufacturers, I think I just put propshaft manufacture into Google
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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Bob C
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| posted on 3/3/04 at 11:02 AM |
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hooke joints & cvjoints wear out faster if they're perfectly straight - I think you're supposed to have a degree or so at least so all
the wear doesn't happen at a single "point".
If the yokes are aligned 2 hooke joints on a prop with parallel gearbox o/p and diff input will give overall constant velocity - the diff end corrects
the errors put in by the gearbox end, but the prop in the middle has the wobbly speed thing going on.
Sorry - grannies sucking eggs etc. - just thought I'd point it out.
Bob C
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Mark Allanson
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| posted on 3/3/04 at 10:04 PM |
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The wear is called Brinnelling and is caused by the roller bearings acting on one spot instead of 'rolling'. With a bit of agle on the
UV's, the rollers rotate around the bearing case.
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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Peteff
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| posted on 4/3/04 at 11:20 AM |
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It is simply known as "wiping" where the lubricant in the joint is not distributed over the roller but is cleared from one spot allowing
the hardened surface to be breached. It used to happen when cars were delivered by train and rolled forward and back when the train slowed and
accelerated and knackered wheel bearings on brand new cars before they got on the road. Little bit of history there.
yours, Pete.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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MikeR
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| posted on 4/3/04 at 12:53 PM |
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and how did they discover it?
Some american car manufacturer stopped making cars on the west coast. Kept making them in the east and shipping them. All the cars on the east coast
where fine, the west coast ones had the problem .... took them a while to realise what was causing it mind you.
a litle bit more history 
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britishtrident
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| posted on 6/3/04 at 02:40 PM |
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Angles should be OK but I would be uneasy about having the joint between the two shafts slap bang in the middle -- as suspect the shaft could
start to whip at critical speeds.
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