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garymorton
04-09-2013, 01:59 PM
Hi,

This is my first post - long time lurker but most questions seem to have been asked already!

Has anyone had any experience of using aluminium for the stubshafts that connect the output spline on a Torsen diff to the tripod joints? Last year's car has shafts made from 4340 (I think) and do the job OK, but obviously are fairly weighty, so we're debating switching to 7075. If we do this we'll use the inserts that Taylor Race use so the tripods don't eat the stubs! I have some FEA going on it, but the way I'm setting up the constraints (Creo Simulate) is telling me the stresses where the splines end way above the failure stress of the 4340. Any tips?

I can remember seeing a thread somewhere about someone doing this and the shaft shearing right through between the tripod holder bit (technical term) and the splines, however can't seem to dig it up from anywhere! If you think this is a bit late for this year's competition - we are running a 2-year 'plan' with design this year, then build over the summer leaving next year for testing and upgrades etc.

Cheers

Drew Price
04-09-2013, 05:40 PM
I sheared splines off an un-heat-treated 4130 shaft that I cut for our car. I'd have a hard time believing AL would hold up because of the small diameter that you're driving.

You could always thru-drill the shafts and press a seal into the end. Think small cupped freezeplug type plugs.

spoles
04-10-2013, 06:57 AM
splines are too small on a diameter less than an inch. Run FEA on the splines and you'll come up with a FOS just above or right at 1. Then factor in fatigue and there's not a doubt in my mind they'd strip.

Dash
04-10-2013, 10:32 AM
I'm with Drew on this one. Just bore the stub out and then turn a little plastic or aluminum plug for the plunging system to run against.