idea for high ground clearance axle

[aspera]

I've been reading up on portal axles a little bit and love the way that they work. But I don't see them hitting the showroom floors on a new vehicle anytime soon. I don't expect aftermarket portal conversions (to normal axles) either. Portals main advantage is ground clearance, either on solid axles or on IRS/IFS (Hummer). Normal independent suspension starts with the advantage of ground clearance too...but can loose it on rough ground.
Conventional solid axles are simple, cheap and strong.


Maybe there is another way. Why not cherry pick the best from all of the designs? I'd like to see a solid axle with a raised differential. Basically, it would be like IFS, but without suspension movement. Everthing would be frozen in the high ground clearance position.

I'm no expert, but here's the basic idea. Start with the differential in the middle. Use strong inner and outer joints on halfshafts to get the power to the wheels. Build a truss that is higher in the middle and lower on the ends to mount everything in place. Like a bridge.

The halfshafts angle downward a few degrees on this design. Conventional solid axles have zero degrees drop (side-to-side). That looks like room for improvement. In addition, increasing the halfshaft angles can decrease the driveshaft angles.

The hardware for an axle like this wouldn't be too exotic. If you wanted to go overkill, I guess you could build the halfshafts exactly like short driveshafts. Otherwise, a full size truck IFS might be the best place to start.

I also like the fact that since a normal diff is retained, you can use available lockers. No fancy portal gear boxes are used. SMALLER tires can be used with MORE ground clearance. That means that less stuff breaks and gearing is lower.

 

[StuckXJ]

It sounds like a good idea, it would probibly require extra bracing over a conventional solid axel but seems like it would be worth the gained ground clearance. Now all you need is someone to make it.

 

[CW]

The early 80's ford IFS was almost a combination of a solid axle and modern IFS. They had a d44 pumpkin that had IFS shafts going down to the hubs and a skid was built around the shafts and the coils were aslo mounted to that skid. You could probably mod one of those to come up with somthing very similar to what you are describing. Why is this in the S&P forum?

 

[aspera]

I didn't know where to post it. Sorry. Maybe you need a forum for crackpot ideas.

Good call on the Twin I-Beam suspension. I forgot about goofball independent suspensions like than and Mercedes' old IRS. They just have one joint in the middle. http://www.mbzponton.org/valueadded/maintenance/swingaxle.htm

 

[Root Moose]

Maybe there is another way. Why not cherry pick the best from all of the designs? I'd like to see a solid axle with a raised differential. Basically, it would be like IFS, but without suspension movement. Everthing would be frozen in the high ground clearance position.

I'm no expert, but here's the basic idea. Start with the differential in the middle. Use strong inner and outer joints on halfshafts to get the power to the wheels. Build a truss that is higher in the middle and lower on the ends to mount everything in place. Like a bridge.

The halfshafts angle downward a few degrees on this design. Conventional solid axles have zero degrees drop (side-to-side). That looks like room for improvement. In addition, increasing the halfshaft angles can decrease the driveshaft angles.

This isn't a terribly new idea - it's used on some military vehicles (Duro comes to mind). Do a google searcha nd you should be able to find images. If not let me know and I'll dig something out of my gallery here.

The Duro uses portal boxes at the axle ends as well.

Not sure what you'd call these axles - modified De-Dion I'd suspect.

Oh, actually, now that I think about it, the Duro design is a little different than what you have in mind because the diff assembly is solid mouted to the body.

r@m

 

[aspera]

This isn't a terribly new idea - it's used on some military vehicles (Duro comes to mind). Do a google searcha nd you should be able to find images. If not let me know and I'll dig something out of my gallery here.

The Duro uses portal boxes at the axle ends as well.

Not sure what you'd call these axles - modified De-Dion I'd suspect.

Oh, actually, now that I think about it, the Duro design is a little different than what you have in mind because the diff assembly is solid mouted to the body.

r@m

I found a little on the Duro, but not the axle. In my idea the differential isn't mounted to the frame. Put another way, imagine an ordinary independent suspension where the shocks and springs are replaced with rigid rods. Then the whole rigid setup, including the subframe that it is mounted to, is sprung with leaf springs. That gets you into the ballpark.

EDIT: I just read up on the Duro's De-Dion axles. Cool. It has inboard brakes too. Sweet. I suppose that inboard brakes could also be incorperated into my dream axle. I have a big hardon for inboard brakes. You should have seen me trying to take a picture of the underside of the NSU in the Imperial Palace Collection in Las Vegas. :looney:

That's the same kind of axle that I saw at work the other day on a new Kubota RTV900. The DeDion tube was also a receiver hitch. That seemed like a more direct load path for towing, instead of through the suspension.