Half-Shaft Design

[quincy100]

I have to design half-shafts for a special FWD application, and I'm not familiar with the application. So I have a couple of questions:

1. During bounce, the wheel-to-transmission distance will change due to suspension geometry. The inboard CV joint will be fixed at the transmission. Do I allow the splined (outboard) shaft of the CV joint to slide inside the spindle to account for the change in distance?

2. Is it critical to locate the outboard (steering) CV joint on the steering axis? If the outboard end slides (laterally) then the location of the CV joint center will also vary in relation to the steering axis.

Anyone know of a paper on the applications criteria of half-shafts for FWD vehicles?

 

[MikeHalloran]

I have the impression that old FWD designs used ball splines in the shaft, and newer designs use inboard joints that allow some axial motion, e.g. three- ball joints. I don't think you'd like the results of putting the outer CV joint anywhere but in the steering axis. So far as I know, the splines between the CV joint and the hub are there only to allow assembly, and are not intentionally lubricated, and not intended to slide, ever.





Mike Halloran
Pembroke Pines, FL, USA

 

[GregLocock]

As Mike says. Your idea in (1) won't work for very long. Use a plunge joint at one or other end of the halfshaft

(2), no, but you'll find that you only have limited plunge in the plunge joint so you can't sacrifice too much by moving the ball away from the steering axis.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[quincy100]

Thanks guys. You've been a big help. It looks as though I need to locate the outboard CV joint on the steering axis, and then use a plunge joint at the inboard end to account for lateral movement in the suspension.

 

[GregLocock]

That's the usual way.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.