Planning/Imminent build of 4x4 kart

[Iron John]

Engine turns a generator.

Each axle has a little straight section in between with a spur gear, chained to an electric motor.

Add a battery as a buffer.

Perhaps a simpler drivetrain?

 

[Iron John]

Well more thought has gone into this kart with the arrival of the silver fox . Starting to drift from the one link/panhard bar idea because of unneeded complexity and weight, besides sourcing expandable u joints or cvs at this scale is difficult and the ones I can find are expensive. So the new idea is a swing-axle sus. What if I put the axle on a single hinge pin to swing on, this would facilitate tons of travel, and minimum cost, weight, and complexity. This hinge point would also be the Drive Shaft, meaning that the DS and the axle hinge rotate about the same axis. I do realize the massive camber changes the wheel experiences throughout travel, more than a link sus. The also major setback is that the sus. cannot "bump" all together, like if the kart went over a speed bump straight on, the sus. could do nothing because it would not activate the swing hinge pin (DS). You could straddle the speed bump and activate the sus. The last problem would be the twist when the DS is turning, its going to cause the axle to want to turn on that same axis, I think this can be solved with shock tuning.

If anyone is familiar with the euro trucks Tatra, they have a sort of similar setup where the axle half shafts rotate on the same axis as the DS.

Can anyone see why this would/wouldn't work?

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Backbone

Glad you listed this as I was thinking of suggesting it.

It will work just fine and with the low speed you are anticipating there is no need for independent suspension.

On the Tatras and similar vehicles, the entire driveline is enclosed. Check out the final scenes of the newest Mad Max movie where the tanker is finally blown up. When the tractor overturns you can see a great view of this type driveline.

 

[bread]

Engine turns a generator.

Each axle has a little straight section in between with a spur gear, chained to an electric motor.

Add a battery as a buffer.

Perhaps a simpler drivetrain?

Thats a good idea, but I'm not looking to spend the kind of money that would go into it, and if there was a motor on each axle, how would I get it to pivot? Weld a bracket above the motor and spur?

Found this 4 way gearbox, but they look heavy and expensive

http://www.screwactuator.com/product/torque-reduction-90-degree-gearbox-4-way.html

 

[Iron John]

Thats a good idea, but I'm not looking to spend the kind of money that would go into it, and if there was a motor on each axle, how would I get it to pivot? Weld a bracket above the motor and spur?

Found this 4 way gearbox, but they look heavy and expensive

http://www.screwactuator.com/product/torque-reduction-90-degree-gearbox-4-way.html

I was thinking of a staionary jackshaft in the center with the motor mounted coaxially (transverse). Then u-joints with stub axles out to the wheels.

I agree that would require a lot of parts and $$.

Or, the swiveling diff approach with the motor mounted to the diff. Or maybe with a vertical shaft engine (two engines! yay!) that pivots with the diff.

So many possibilities, each with its own can of worms.

 

[BigMark408]

I would look into using an actual transfer case and make some drives to adapt. That'll give you 2H,4H,4 low.. much much better for trails and crawling..

 

[itsid]

Lets call it a crawler then, even so I realize that much travel will never be used, but yes probably coil overs will be the choice. the real question now is what kind of gearbox would work for this ?

It has to have four shafts because I think the axle would need two pivot points on the DS to be strog. I really can't find any gearbox of this type, anyone have ideas ?

My worm gearboxes won't work at this point because the input shaft doesn't come out the other end of the box

well first:
the shaft doesn't HAVE to come out of the gearbox to make it work...
you can mount the gearbox case to a pivot and just scrap the last pillowblock on each end.
So the wormgear is back in the game, and an ordinary (or say more ordinary than four way) three way gearbox is just fine.
You could even (if the gearbox case is weldable) weld a bolt to it and use the pillow blocks you have in your drawings

second:
articulation isn't (shouldn't) be a big issue either.. just find big (as in long and beefy) coilovers and control them with a lever..
long side on the A-arm .. short side on the shock and depending on the leverage ratio you'll reduce the travel by the same amount
(you need to compensate travel by force though.. so think truck rather than car I guess )
Or use the A-arm as your lever and just attach the shocks on the A-arm as close to the chassis as possible (practical) that's basically the same idea.

'sid