Electric Wheel Motor(s) for Lawn Tractor

I can't remember what they were called, or a brand name, but there are electric motors that are sensitive to slip and tend to run very closely at the same speed, without being exactly synchronized. Something like this might work well in your app. (Sort of like an electrical version of Posi-Traction.)

If you are going to use this on a snow removing device, why not just use solid axles connected by a torque limiting clutch. The front to rear drive could be connected by a speed sensitive clutch, like a chain saw. Another option might be to use the electric clutch design from a better riding lawn mower.

BTW, welcome to the insanity.

7-06027. picture failure again.

This electric clutch is sold by NAPA for around $250, and is rated for 105 ft. lb.torque. If the engine drives a solid axle shaft, with this mounted to it, and a belt from the clutch to the solid axle on the other end, all wheel drive is achieved when needed, released when not. Just another option. Not as sophisticated as the hydraulic drive, but still 4WD.

For low speed high torque hydraulic is far better and cheaper. Just by using the proper type of flow dividers you can get full time all wheel drive with equal speed and torque while still being able to steer properly.

Do you think the cost of 4 hydraulic motors will exceed the cost of the clutches and differentials?

You could always use your dual differentials and drive them with two hydraulic motors run in series and a variable flow rate pump.

I doubt it being he only wants around 2.5 HP on average at each wheel.

Small hydrostatic traction motors that size can be found new for around $100 - $150 plus the three flow dividers would probably be around $50 - $75 each.

It depends on how elaborate he needs or wants to get with the design. Honestly form my experience when low speed high torque with high reliability is wanted for small variable speed and heavy load operation hydrostatic drive is tough to beat.

Thanks for all the imput.

Lots of good suggestions and comments.

Emjay..I went to that site, but didnt see the "Arcs and Sparks" section....is it hid under some other heading?

tcmtech; as re the hydraulic motors route, where would be a good source for those motors & flow controls? Would the hyd schematic be easy to design? How would the steering position be used for input to the flow divider?

Would the flow control/flow divider need to be a "special"?

I've read a little about using electronics as part of a hydraulic drive (which would seem to be the best of both worlds), but haven't persued that yet.

thanks again

gatz

You can get hydraulic motors online in countless places.

As far as the hydraulic line lay out goes its very simple. The variable displacement pump feeds to a 50/50 flow divider that splits the flow front and back and each of those outputs go to another set of 50/50 flow dividers for each axle.

The only additional option would be to add three solenoid valves that allow the outputs of the three flow dividers to each be added together so that they work like a standard open spool differential but can also be each locked up independently for equal speed at all wheels regardless of traction or set in other combinations as well.

Gatz,

Last time I used the Website I was able to look at back issues.

When I got home last night there was the latest issue of AME waiting for me and the first article in the book is on on home made electric traction utilising automotive alternators. I haven't had time to fully read the article yet (I've looked at the schematics) and may contribute when I do. It looks like a really good starting point for your project.

That sounds interesting to me. Please post contact information if it is available. Thanks.

Bob,

I did a snip of the page for the current issue at AME but cut not paste or attach it. I'd suggest look at the site from my last link and click on Current Issue.

As well as the Alternator article you will find Richard Schurman discussing electric traction in full size equipment. I'll look closely at that article when I get 5 as traction is my specialty.