Kubotasaurus, a home built micro tractor

[chaffe]

also i looked up the specs on my motor, 700 n/m at 2500 psi, plenty of torque available, especially as it goes through a 4:1 reduction in the diff :thumbsup:

 

[chad22]

well, that will be coming soon, i hope to get the seat on and make it more "drivable" before i make a video! (not wanting all you lot laughing at me falling off the back!)

Come on now. We'd all love that video of you falling off the back. :laughing: "As long as you don't get hurt in the process".

Can you drive it standing up to the side? I used to do that when I was a kid. I'd stand on the side of the lawn tractor and drive it. "And no not while the blades were engaged". Now that would be dumb.

I fell off once too and I wish I had caught that on video. lol

When I was about say 10. I was towing a friend "he was 8" on another broken down lawn tractor. We were going up a curb and I had told him not to try to ride the side of the curb or he'd flip it. What da ya know. I got caught on the side of the curb and ended up flipping mine.

Luckily I didn't break anything, or worse.

Chad

PS. Sorry for going off topic. I'll quit rambling. lol

 

[chaffe]

ramble away chad! I did fall off yesterday lol, its quite "touchy" on the hydraulics when you are steering with one hand and holding on for grim death with the other, on the hydraulic lever! :laughing:
Never did much tonight, working 10 hour shifts and driving another 2 hours on top of that fairly makes me tired! but here is the result of an hour in the garage;

Ill get the seat on now, going to use two bits of 2" box at a slight angle to the rear for that, all will be reveiled soon!

 

[dfkrug]

The good thing about the hi-lo pump is that it automaticaly "drops" downd a gear when the load increases on the transmission, quite ingenious if I may say so (and just lucky!) i hope this clarifies what i am trying to achieve, and thanks for the intrest again, chaffe

Nice work, CHAFFE.

A 2-stage hyd pump is a great way to go with these small engines. I wish
I had one when I built my CADDigger years ago. Even with a 10hp engine,
the cylinders moved slower than I wanted in low-load situations.

The reason you want a "motor spool valve" is to avoid the large pressure
spikes that you get when braking, esp when you have a lot of momentum
to stop. The M-S valve will allow the drive to free-wheel a bit when you
return to neutral. Some have adjustable reliefs, but you can also install
an after-market relief valve in the system to avoid problems. You also
may want to have additional brakes as this will limit your hydraulic
braking action.

 

[chaffe]

Nice work, CHAFFE.

A 2-stage hyd pump is a great way to go with these small engines. I wish
I had one when I built my CADDigger years ago. Even with a 10hp engine,
the cylinders moved slower than I wanted in low-load situations.

The reason you want a "motor spool valve" is to avoid the large pressure
spikes that you get when braking, esp when you have a lot of momentum
to stop. The M-S valve will allow the drive to free-wheel a bit when you
return to neutral. Some have adjustable reliefs, but you can also install
an after-market relief valve in the system to avoid problems. You also
may want to have additional brakes as this will limit your hydraulic
braking action.

Thanks, And yes the 2-stage pump works very well in my experience. It makes the best of a not ideal situation.
Interesting that you mention the shock when the drive is halted, it skids the wheels very easy, although there is not much speed involved it still might make a mess of the grass if im not carefull with the drive pedal. I had thought of some kind of relief valve or "run on valve", or prehaps even a damper on the footpedal so it can only return slowly. I would be quite interested in any more information you may have about relief valves in the drive (i dont really want to change my spool), thanks Chaffe..

 

[dfkrug]

I would be quite interested in any more information you may have about relief valves in the drive (i dont really want to change my spool), thanks Chaffe..

I understand that you don't want to buy a different valve.

If you put a separate relief valve, connected between the 2 work ports
of the spool valve, this would provide a path for the oil when the
pressure spikes as you release the lever to neutral. You will also want
another RV, connected in the reverse direction, to handle the reverse
flow. You can use adjustable RVs, but you don't really want
to set them below your working pump output pressure. Not as good
as a motor-spool valve, but better than nothing.

I would also put in a control lever damper, as you suggested.

Note that in a hydrostatic transmission, the pressures are much higher
so the pressure spikes are not the same kind of problem that you have
with a gear pump and hoses.

 

[chaffe]

DFKRUG, thanks for the advice, i will certainly look into something of this nature.
Here are some high quality pictures of it with the seat on, this is essentially finished now bar the footplates. I can now count the lift linkages as seperate projects, the first thing to do is look at mounting my mower deck, as that is of primary importance this time of year!

thanks for looking :tractor:

 

[Johndeere3720]

DFKRUG, thanks for the advice, i will certainly look into something of this nature.
Here are some high quality pictures of it with the seat on, this is essentially finished now bar the footplates. I can now count the lift linkages as seperate projects, the first thing to do is look at mounting my mower deck, as that is of primary importance this time of year!

thanks for looking :tractor:

Looks like the real thing, only smaller. :thumbsup:

 

[Petroman1]

That is AWESOME!!! :thumbsup: Great job.

 

[J_J]

Have you considered the fact that a fully functional mower deck, one two or three bladed, will take just about all of the HP that the engine has.

A lot of single bladed lawn mowers have up to 6.5 HP available. .