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View Full Version : Dixon Z transmission? (zero turn mowers)



Jim Shaper
02-24-2011, 07:56 AM
I'm contemplating a tracked or multi wheel ATV build and am intrigued by the zero turn mower transmissions.

How robust are they, and how difficult to repair are they?

Anyone ever built something like it?

Boucher
02-24-2011, 08:25 AM
Since about 1993 Dixon has used individual hydrostatic motors on the rear wheels. Previous to that they had a cone drive transmission that requirred a lot of tweeking to keep them working properly. I don't know if the individual motors are geared to the wheel if that is what you are inquirring about. The wife uses ours to pull limbs an brush to the burn pile. I have a Dixon that I bought in 95 still works great. The new Dixons are very poor when compared to the older ones. When I needed another mower I went with a new Torro. The Surplus Center has the pumps, motors and control valves for these type of builds.

Jim Shaper
02-24-2011, 08:32 AM
I know a guy who's got a dixon chassis for cheap with the old cone transmission intact and functional - but at the same time hydraulics is a whole bunch more forgiving to overload...

I was wondering about the transmission mechanism, the rest I can handle. ;)

I'm a hydraulics noob. :o

What size/type pump would you need to make a vehicle capable of pulling a decent load (like pulling a disk) as well as maintaining a bit of speed (not while pulling the disk)? Which motors would you suggest?

Flying-Phantom
02-24-2011, 09:00 AM
define functional!
A cone drive dixon, unless it has not been used, will require new bearings, new chains, new sprockets, and probably new cones and bearing housings. Look at the cones, if they have a shoulder or look at the chains and if they sag the machine has a lot of use. Dixon is rebuildable but EXTREEEEEMLY frustating. Correct adjustment to get the handles even like they should be, takes many hours of tinkering. Been there done that.
The mechanical dixon won't pull very much. The hydraulic "Hustler" hillside diesel version would have the weight and the power to pull a disc.

Jim Shaper
02-24-2011, 09:05 AM
That's what I'm asking - what components would be necessary to assemble a hydro-drive which would do the task of pulling a disk and a trailer?

I have no intention of buying a mower, I just wanted to know if the drive was stout enough for the intended tasks (which apparently it isn't).

So now that we're talking hydraulics, what components are we looking at? How much HP do I need for a capable pump? I know some of the skid steers go upwards of 50hp, but that's way bigger than I want to deal with.

Vehicle weight will be 1000lbs or so loaded (depending on drivetrain). Additional weight can be added for traction.

dockterj
02-24-2011, 09:39 AM
Look at a John Deere 140 garden tractor. It will do everything you are talking about with a 12-14hp single cylinder engine. The hydro is a sundstrand:
http://www.wfmfiles.com/download/Sauer_Danfoss_(Sunstrand)_Technical_Information_Se ries_70_15_Pumps_Motors_Transmissions(BLN-10006_RevB_Jan93).pdf

Power is less important than gearing and getting the power to the ground.

Mike of the North
02-24-2011, 10:20 AM
There is a Yahoo group for tracked lawn tractors, you should be able to get some answers there.
http://groups.yahoo.com/group/tracklayinggardentractors/?yguid=248101580

Black_Moons
02-24-2011, 12:01 PM
I allways wonder why we don't see more hydrostatic CVT transmissions..
They are used on lawn equipment.. And the serious industral trucks that roam around some quarys...

So, Clearly they scale up :) And can handle some serious abuse, I doubt those people baby em. So why not cars and trucks?

Is it they are just not very suitable for high wheel rotation speeds or something?

RTPBurnsville
02-24-2011, 12:43 PM
Jim,

Not sure how big of disk and trailer you are wanting to pull.... I have a 15HP, diesel powered Kubota which is all hydraulic and it has an amazing amount of power for it's size. Checkout the tractorbynet.com webpage for lots of info on this type of thing.

Robert

SVS
02-24-2011, 12:47 PM
Jim,
There is no cut and dried answer to your question, you need to spend a little time on Surplus Centers tech section, and then start looking through their selection of pumps and motors for suitable matches, plus formula to equate engine horsepower(torque and rpm) to hydraulic horsepower(flow and pressure)

You will need a hydrostat pump (varies flow from full forward through zero to full reverse) and a motor. Pump will be rated max gallons per minute, motor will be sized in cubic inch displacement per revolution and inch pounds torque at max pressure. This info plus tire size or intermediate gearing will let you select a suitable speed/torque combination.

It's equivalent to sizing sprockets or gears to balance torque and speed. (Little pump, big motor=slow and powerful. Big pump, little motor=fast and weak.)

If you want a Zero turn machine you need two pumps(or a tandem pump) plus two motors. There are combined pump/motor units which have both elements inside a common case, but this is probably a less flexible solution for a home built machine.

Does this make a lick of sense?

Black_Moons
02-24-2011, 01:00 PM
I think there are a few diffrent ways of doing zero turning radius.

You could have two variable pumps and two fixed motors.
Or one fixed pump and two variable motors (Wasteful at idle without manual pressure release?)
Or one (variable?) pump, two fixed motors and some valving (though turning might become dangerious/hard to control at speed if you used this method, without standard steerable wheels)

SVS
02-24-2011, 01:41 PM
You could do it with mice on treadmills if you felt the need but standard practice with commonly available parts is variable pump/fixed motor.

tdkkart
02-24-2011, 01:43 PM
I've always thought that using the engine/trans/differential from something like a 12-20HP hydrostat Deere or Cub garden tractor would work. Drive direct or chain reduced from the rear wheel hubs, and then use a pair of indivdually activated hydraulic brakes for the steering. The hydro would provide your variable foward/reverse speed, a slight chain reduction could be used for a bit of added power plus you don't really need a crawler that will do 12mph.

kf2qd
02-24-2011, 04:06 PM
Unless you are going to go for a set of steering wheels (like a halftrack) a trans/diff off a garden tractor is going to be very frustrating. The only control you would have would be brakes and you would have to coordinate your speed control with braking to control your ground speed and you would only be able to shut off one wheel for turning, and you would always be replacing brake pads, and you would either be forward or revers with both wheels. Using seperate drives for each wheel makes it easier to control ground speed, as well as allows you to reverse direction on one track while going forward with the other. A normal tractor transmission would work if you locked the Diff and made turn clutch/break units like a conventional dozer(or more properly, crawler as a bulldozer is really an attachement for a crawler).

Guido
02-24-2011, 04:10 PM
http://thekneeslider.com/archives/2007/05/22/hydrostatic-drive-diesel-motorcycle/

All you need to know. Takes you from start to stop to finish to look forward to examine back------------------ to different ways that it is being done.

--G

Jim Shaper
02-24-2011, 04:51 PM
Actually, I'd like something that can do 30mph on paved roads, but still have enough power to pull 4 cords of wood up a hill. :)

My other idea was to get a small honda fwd engine and transmission and configure some form of independant clutching mechanism to disengage either axle (the transaxle differential would be spooled). There again, I'm not sure how robust their transmissions would be under a constant heavy load. I know the kids have put them against considerable horsepower (350+), but that's pretty short durration abuse.

CCWKen
02-24-2011, 05:02 PM
Yikes! Don't use those zero-turn HS units for ground engaging implements or to haul much weight. They just won't hold up. AND they're very expensive to repair/replace. If you want to go hydraulic, use a separate pump and drive motors designed to carry outboard weight and have the wheel flanges. A big engine to drive a big pump will give you plenty of ground speed. The right motors will give good torque for pulling.

Buying all this stuff new can get mighty pricey. You'll need control valves too. You'll need at least 12-15hp at you're pump's rated rpm. You won't get that except by going diesel or using a 25hp+ gas engine. Unless, of course, you plan on running the engine wide open all the time.

You might be better off buying a used tractor and getting everything you need in the right tool.

Jim Shaper
02-24-2011, 05:09 PM
A used tractor won't go over a swamp. ;)

becksmachine
02-24-2011, 05:29 PM
My other idea was to get a small honda fwd engine and transmission and configure some form of independant clutching mechanism to disengage either axle (the transaxle differential would be spooled). There again, I'm not sure how robust their transmissions would be under a constant heavy load. I know the kids have put them against considerable horsepower (350+), but that's pretty short durration abuse.

I guess I view automotive horsepower ratings (claims?? ;) ) with extreme skepticism.

In any event, adapting automotive components to what is essentially agricultural use can be a real can of worms.

Methinks the speed ranges are all wrong. To use that Honda setup, you would need some sort of outboard speed reduction (planetary gearboxes?) to achieve useful ground speeds in anything but first gear at an idle.

Dave

Jim Shaper
02-24-2011, 05:34 PM
Having seen the components and being present when dyno'd, I know full well the horsepower was indeed there. I, however, would be using the engine bone stock - so in the 120-140hp range with maybe 100lb/ft torque.

Also, the gear reduction will be there. I'm not talking about direct drive off the auto's differential. Low engine rpm and high output speed would be pointless in this application. Using 5th gear would likely never happen, but when you can buy the whole car for 500 bucks, it's not worth complaining about a couple extra selections.

justanengineer
02-24-2011, 06:50 PM
I laugh everytime I hear someone claiming dyno results, but thats because I work around them daily. Not to disagree with you about Hondas, just saying that dyno results are more affected by the operator's error/greed than they are by engine power, and most Ive known are both greedy and a bit dim. I once had a shop owner in NY try to tell me I was making 450 hp when several others had agreed it was around 300.

Back to the original topic, you need to either find a high end mower that truly has hydraulic motors on each wheel, or find yourself a golf course pulling tractor. My dad's got one made by Toro in the 70's, really low from the factory with a pair of monster hydraulic motors in order to pull a gang mower that was around 15 feet wide.

SVS
02-24-2011, 08:43 PM
This page is Surplus Centers current Hydrostat inventory.

https://www.surpluscenter.com/sort.asp?catname=hydraulic&keyword=HPHS

The ZTR tandem pump for $130 might make a 10hp machine.
Two of the $220 Hydrogear might stand 20hp.
The $2000 Danfoss tandem would be overkill, but really bad ass. Even has dual accessory gear pumps for operating attachments. Looks like a pretty serious skid steer loader pump.

Jim Shaper
02-25-2011, 06:33 AM
I'm looking at spending under 2K on the whole project. Used honda = 500 or less, big tires on small wheels = 300 or so, steel = 400, all the other crap = 800.

As for the HP claims - doesn't matter at all. Anything over 40 is bonus. I can also run a big pump off a car engine with a little custom bracketry (enabling a splitter, and even a hydraulic sheer ("jaws of life" for smaller trees) or anything really).

I'd really love to do tracks, but I'm not making my own (too labor intensive), and buying them is far from affordable.

As was mentioned, this thing needs to travel through a swamp. I'm not sure what the PSI the soil will hold in it's "dry" state, but I can tell you I go up to my knee when it's wet (even in the "frozen" state). So I've been leaning towards making it an almost amphibious vehicle to the extent of at least not sinking past a given depth (smooth flat bottom without seams).

MrSleepy
02-25-2011, 08:06 AM
Have you seen any of the "Howe and Howe Tech" videos on discovery...where they build tracked vehicles..in one episode (series2episode04?) to carry a guy and his wheelchair over land and swamps..

Might give you some ideas on whats acheivable.

Rob

Jim Shaper
02-25-2011, 08:15 AM
I've seen that show, and the ripsaw (I think that's what they called it) is what got me thinking of going bigger than the traditional lawn implement engine size.

A motorcycle engine would be another option, but they're not as robust as a car, and not as cheap or readily available (also have less torque).

SVS
02-25-2011, 08:44 AM
I've seen articles in a paper called "Farmshow" where guys cut the beads and part of the sidewalls out of old tractor tires to make treaded belts for buggies like you are thinking of. Seems like one guy cut down a 1/2 ton pickup axle, used the brakes individually for steering, and 3 or 4 minature spare tires per side for track idlers/drivers.

I think they have a website and sell a cd with past issues on it. It's sort of an interesting display of farmer style ingenuity. Some stuff is pretty impressive, some is not.

becksmachine
02-25-2011, 11:21 AM
Hi Jim, I didn't see anything in your price list for a governor? Or additional cooling, both engine and hydraulic?

Not trying to throw cold water on your idea, just sharing some of my (and my father's ;) ) hard won experience.

Dave

Jim Shaper
02-25-2011, 03:39 PM
I'm a complete noob when it comes to hydraulics, which is why I've been leaning towards mechanical/friction based systems thus far.

I've got all the cooling the engine needs with a spare aluminum griffin radiator and a big aux fan sitting on the shelf. Honda 1.6L engines use a radiator about the size of a decent laptop. I've got a core that cooled a 355ci chevy with 10:1 compression.

There's also a bobcat 500 that recently showed up on CL here for 2K. If my land deal happens (should know today), I'll have some extra coin left and might just spring for that and then work on how to float it. If they don't take my offer, I'm not going to need the utility features anyway, and will end up buying a regular atv.

jdunmyer
02-25-2011, 07:32 PM
Many (most?) industrial-sized hydrostatic drives incorporate a gear transmission after the hydraulic motor(s). My lawn tractor, for instance, is a 15Hp Diesel outfit that has a 3-speed transmission inline with the motor and differential. This gives me "low" for rototilling or very heavy mowing, "medium" for mowing the lawn, and "high" for tooling across the farm at maybe 8 Mph. Some years ago, I had a large trencher used for field tiling, which had a 200 Hp engine. It had a 4-speed transmission in the system, with "low" for digging, "2nd" for running back across the field, and "high" for going down the road.

There's a couple of I-H hydrostatic drive tractors here at the FF show, I'll make a point to look them over tomorrow to see if they're the same.

The problem is that if the hydraulics are geared for road speeds, there will not be enough torque do do any pulling at low speeds. Gear the system for the necessary pulling torque, and you won't be able to get satisfactory road speeds.

As others have said, Surplus Center and Northern have all kinds of information in their catalogs: be sure to use such info if you wish to avoid expensive mistakes.