All-Wheel-Drive Go-Kart!

[Smurph]

That's right. I want 4 drive wheels.


That's my basic Idea for my drive line. I'll get more detailed plans when I get back home to my computer with Autodesk Inventor on it. I want to mount my engine sideways from the typical setup. The crank shaft will be parallel with the black line in that, the main drive shaft. I plan on using something similar to the rear axle and differential found Here (NorthernTool.com) as my main drive shaft (The black line. Differential depicted as orange box)

The tricky part: The blue boxes, or differentials.

Does anyone know of a place to find such an item? Ideally, just like the differential found in the back of front engine/rear wheel drive cars, but I need it to be much smaller. Maybe a 4-wheeler has parts that I could easily use?

I already plan to have to make these parts. I have access to heavy-duty CNC machines, and I know the principles of how differentials work very well.
If I can't find the differential, I'll need help locating some strong beveled gears, and the diagonal tooth master and slave gear found in a differential. If anyone knew where to find these parts, or have them for sale, that would be amazing.

 

[frederic]

The Northern Tool axle you posted a link to has a differential, though the drive direction is inline rather than perpendicular.

There are many sources for a differential, and I just went through this myself. If you're kart's somewhat big you can use automotive differentials (housed or not) and there are many small cars with tiny differentials. Another option is farm equipment, particularly tractors which often have perpendicular input shafts. Be forewarned however, they're usually cast iron and heavy.

beveled gears can be purchased from "MSC" or McMaster-Carr if you want to go that route.

Many mower transaxles have differentials that are fed perpendicular to the axle shaft, and it's just a matter of finding one.

 

[Smurph]

Yeah, the axle and differential (Black line and orange box) like the one found in that Northern Tool link will be where the power transfers from the engine to the drive-train. I'll lengthen the axle using u-joints if necessary. I'll most likely put a sprocket onto that differential and drive it that way. This will allow the power to transfer from the front to the back as necessary (Doing the job of a transfer case). I'd really be interested in making this differential Limited Slip if possible. Then I'll have my front and rear differentials giving the power that they receive to the left/right wheels where necessary as differentials do.

 

[freakboy]

if your powering the shaft you should use right angle gearboxes into the diff's.

 

[frederic]

Here is an idea for you that will simplify all the mechanicals and reduce weight significantly.

Run two Northern Tool axles, one front, one back, and chain them together the length of the kart, and insert the engine into that chain at the back with a tensioner, much like a bike tensioner.

Cover the chain with a shroud so you're safe at all times.

There's your *easy* all wheel drive.

 

[anderkart]

Hey Smurph, If your interested theres 3 pics of an all wheel drive kart here:
http://www.affordablegokarts.com/
(click on the lower right pic)

 

[t0x1k]

Just find a rear differential out of a newish car with independant rear suspension. Buy 2 and viola. Just need steering knuckles and the right size bearings to hang the shafts.

Or an ATV with 4wd.

 

[572bigblock]

Thats a very clever idea for AWD. I thought about doing something similar to this, but it might not work out as well. The only difference is that I thought about using a mower transaxle in place of the differential in yours. If you could lock both axles together it would supply power to the front and rear differentials, and act as a transmission/transfercase with multiple speeds + reverse. Some old garden tractors even had horizontal shaft engines with horizontal input on the transaxle.

Using the differential from a four wheeler might not get you anywhere. I believe most 4-wheeler engines are mounted in a position like in motorcycles, so the rear end would look similar to the differential you linked too. Same with golf carts too. But I can't say for sure that EVERY 4-wheeler is like this.

Like said above, many cars have tiny differentials, and you wouldnt have to use to whole housing, just take the ring and pinion, and make your own.

 

[Smurph]

Well I'm trying to keep my weight down. Anyone know of one that moves rather easily, and weighs something close to about 10lbs?

 

[mike75925]

there are some atvs with diff, but their weight is their drawback. i think the northern setups without sprocket come in pretty close to 10lbs. plus on atv side is they will last for a while. comet offers locking diffs, and diffs. don't know prices. and if you want a good diff'ed 4wd, i'd look at how subaru did theirs. the wheel that slips sends it's power to the wheel that grips, looks like a clutching mech.

 

[Smurph]

I'll be okay with it not performing quite as well as Subaru's all wheel drive setups do. Since Subaru has millions of dollars, many top-notch mechanical engineers, and lots of years of experience producing exclusively awd platforms... oh, and computer controlled differentials. I'm a software engineer and don't even want to tackle that.

I think I can work off of three of the differentials I found above. I've seen the same thing used on ebay for way cheaper. I'm going to wait around to find some good deals.

 

[IHcubguy]

I'd really like to see how you get it to steer! are you using half shafts, cv joints?

 

[572bigblock]

you could make the whole front axle pivot around a center point. Like a coaster wagon!

 

[Raywelder]

heres a little different setup.
http://www.affordablegokarts.com/RaceKartsProjectKarts&More.php
Also, if you need u-joints for your front axle, I have 1"bore to 1"bore keyed, never used set of u-joints.

 

[Smurph]

My friend just informed me that he has a 17hp mower engine, as well as a dirtbike engine (unsure of the size) that might get donated to this project. Adding a third pedal for clutch and tying it in just the same way as you would a clutch lever on a dirtbike would be almost no more effort. Bringing the shifter to the front will be minimal work, as well.

This project is really coming to life.

 

[Smurph]

That's what I have so far for the front-end. I haven't made the first measurement, but that's pretty close. 24" wide outer rails. The weird thing up front is supposed to be a differential with a ring gear on it. (didn't decide to get too detailed) The main drive shaft will have a pinion gear on it that will turn the ring gear.

I'll probably mount the front differential on by grabbing ahold of the axle between the Universal Joint and the differential on both sides of the differential.

This ought to give you a good idea of what's in my head.

 

[Smurph]

I might not center the differential. That's a bridge to cross when it gets here.

I got a three-wheeler donated to me. I know that the engine doesn't work. I'll go in and try to find out why and possibly fix it/use it. There will be other parts on it that I'll find useful.

I want some good power. I think I want to have a top speed of about 40-50 on flat ground.

Because of the differentials, it won't raise any wheels. As soon as the front wheels lose traction, the power will be diverted to it, not allowing any more power to lift the car anymore. This is a great advantage over using chains to transfer the power between front and back. Weight can always be overcome by more power. Plus, as far as I'm know, this has never been done before. I'll have enough power to overcome the weight that I add with differentials and additional drive shafts.

Bugatti, a really long time ago, made a multi-engine car for awd, though.

 

[TOO FAST]

I'm just wondering if I understand your drawing correctly, if this thing would turn with
both front and rear live axles. I realize you would have a speed differential from front to
back, but nothing side to side. I think it might not turn very easy (huge understeer?)

 

[Rickracer]

... The weird thing up front is supposed to be a differential with a ring gear on it....

Looks like a front diff to me,

 

[Smurph]

I'm just wondering if I understand your drawing correctly, if this thing would turn with
both front and rear live axles. I realize you would have a speed differential from front to
back, but nothing side to side. I think it might not turn very easy (huge understeer?)

The turning part will be much the same as with the one in the first two pics on the site posted above. Most notably, that second pic. It shows the universal joints that will allow the axle to bend while still rotating. In total, my front axle will have 4 universal joints.

I've also considered CV joints from a civic. They are rather small, and could be used in this application. They most definitely will allow a bend in the axle while rotating. I haven't looked into it enough to see how hard it would be to get them to work in this application.

Also remember that I haven't drawn any of the steering system except for the spindles, which are different than found on normal go karts with no power to the front wheels.