Chain/sproket Driven Independent Suspension?

Just asking on the off chance someone might know exactly how I could implement this.. I'm working on a project, and it needs to have 4 wheel independent suspension. The problem I'm having is the vehicle will be chain driven (motor running a chain that turns the sprocket welded to the rear axle). I don't have a machine shop or access to one or I'd just make a differential, and it has to be executable on a pretty small scale (1/4 scale, the entire length of the truck will be about 3 foot). It also must be relatively cheap, or again I could just outsource my specifications to countless shops that could build a differential for a price.

Anyone have any idea what I could use? Below is a simple diagram, where the red squiggle lines are is where the axle would be able to bend, the arrows show the directions the wheels can travel.



EDIT: Forgot to add I'm aware I could try a U-joint, but I'm not too sure that would hold up in what I'm doing, so I'm trying to find another, more durable way. The axle is going to be driven by a chainsaw motor, so it needs to be able to handle the torque. I'm worried the scale I'm working on would prevent me from making a U joint strong enough.

This may have some parts that may be fitted to your application.

I am not entirely sure this is pertinent to your project (I wasn't a mechanical engineering major at university, but I had a lot of ME friends) :p but the Skid Steer Loader construction machine (aka "Bobcat" after the main manufacturer of the machines before other OEMs got into the market) uses a chain-driven system, powered by a hydraulic motor, as a drive train (it has no transmission other than "hydrostatic transmission"...)

http://science.howstuffworks.com/transport/engines-equipment/skid-steer2.htm

...if I understand your goal correctly, you want to create a similar system with a drive train operating on a similar chain mechanism for the axles.

The Skid Steer Loader has a reversible motor, causing it to "skid" on the opposing set of tyres in order for the machine to turn around (in fact it is designed to be heavier on the back axles so that when it is carrying a load in the bucket the weight shifts to the front axle, thus stabilising the machine, I understand.)

Depending on your motor system and whether it is reversible, you might be able to come up with a similar axle-drive system and chain configuration no? In the case of the SSL, the "axles" are static (technically no axles either in this case) so it differs a bit from your illustrated design.

rather than U-joints, maybe use a couple cheap CV joints from an auto wrecker and couple them in where your squiggles are? Idk how strong an application like that would be or if you're designing it with strength in mind. Also don't know what kinda tire travel you're shooting for. CV setup would be somewhat limited. As far a a u-joint being strong enuf i think it'd be plenty strong if it was done right. Most u-joints are found in real wheel drive cars and those handle torque of v-6/8 engines. If anything i think it'd be more of a challenge to find a ujoint thats small enuf to fit that application. Challenging problem for sure...keep us posted! Good luck!

I appreciate the effort but I don't think that will work in this case.. It's only going to have one drive motor, and it will have no reverse (for simplicity's sake it will have only left and right steering, throttle and braking.)

Although I have always wanted to build a track based system as well, so I'll have to keep that in mind in the future (distant future but still <.<)

If you look at the picture, imagine the red squiggle lines are U joints, I'm looking for something to replace those with. They would need to be pretty small for this project, and I'm worried the torque of the chainsaw motor will rip them apart quite easily.. Not to mention I'm building this after a trophy truck (baja truck) so everything is going to take a beating one way or another.

Also, as far as using an actual hobby R/C transmission/differential, that's not possible for me to do.. Besides the price those parts command I'm trying to do this on somewhat of a budget, the largest common R/C scale is 1/5 and the vast majority are designed around engines entire magnitudes weaker than what I'm going to be using.

Don't get me wrong, I really appreciate anyone taking the time to offer input (never know where inspiration may come from) but neither are really feasible for what I'm needing to do.


I'll check out CV joints.. as for travel, the wheels will be 8 inches, and shocks (which I will be making) will be spring based with 5 inch or so springs. For the U joint, I wasn't planning on finding a U joint, if it comes down to it, I'll make my own, they're not really complex or anything.

Most agricultural part stores would carry a smaller u-joint that would more than likely hold up to anything you could throw at it. Honestly I would be more worried about properly aligning the chain (and using a heavy enough gauge chain) so you didn't lose chunks of flesh when it broke or jumped off of the sprocket.

Well I looked around for CV joints to fit my needs, couldn't find any.. The joints have to be tiny (why I'm reluctant to use U joints all together, a chain is only as strong as the weakest link, and at these scales the metal will get pretty thin).

I finally decided to continue on with my design phase using U joints, I'm still open to ideas, but as of now the plans are drawn with 2 inch long 1/2 inch diameter bored, steel U joints.

On a side note, I can't wait to actually start in on the physical part of this build.