Building a hydraulic rotary mower deck

[tracycarr]

Thanks again.
I looked up power trac.
They sell a 60" for there 25 hp one.
I have plenty of engine just don't know if i have enough ump at the hydr motor. There are 3 turning 30" reels each. There are 3/4 lines to them. That looks encouraging!

I can get a rpm guage or study what the reels turn at but....does any one know off hand?
Toro w/ 7 blade reels. 48 hp for some reson!

 

[Industrial Toys]

This would not be something for the faint of heart. Hydraulic motors are all about math. Flow, pressure, speed. For a rookie to get things right is a million to one shot, I would say. If time isn't an issue and you have some free stuff to play with, then it's a different story. Especially, lots and lots of free oil!

I have a Cushman 10 foot hydraulic three deck mower with a 56 horse power (or so) kubota engine and man, can that thing cut grass. The rating on a thing like that is about eighty acres a day! I had my doubts about being able to transfer power to a mower deck that way, but have since changed my mind.

But, it is so complicated and utterly blows my mind. There are valves, relief valves, case drains on the motors, very scary stuff. It's unusual not to have something leaking as "0" rings get old and they are all, almost impossible to get at with a wrench.

If you are really going to do this, remember that you are dealing with the inertia of the spindles and you can't just shut it off without providing relief. You should have some understanding of such circuits. I do not. When my valves are shut off, and all the mower decks not operating, I still get oil at pressure coming out of either side of the lines to the motors. Makes no sense to me what so ever!

 

[J_J]

Industrial Toys says:

When my valves are shut off, and all the mower decks not operating, I still get oil at pressure coming out of either side of the lines to the motors. Makes no sense to me what so ever!



What you are saying only makes sense if the spindles are still turning.

Once the spindles are stopped, no fluid should flow as the motor spool valve is in neutral and fluid is just passing through the valve.

Put a hyd gage on your deck hyd with the spindles stopped and tell me the pressure.

If you are using motor spools, you don't need a relief across the hyd deck motors.


Actually, your 56 HP engine has enough power to turn a hyd pump, putting out about 27.6 GPM at 3000 psi. So if you spread that across three decks, each deck would be developing about 12 HP, and about 12 HP for the drive.

 

[Industrial Toys]

Well, that's exactly what I figured too. But I had the same experience when I tried disconnecting the lines from the stabalizer on my Kubota R510 backhoe. Oil came out at pressure when the valves were at rest. Go figure, but it makes it hard to run the machine while parts are out for repair, without getting plugs and caps for everything which is not easy either as everything seems to be odd styles and varying sizes. I've found that the only way one could get the right fittings for almost anything hydraulic would be to have your project sitting in the parking lot of the hydraulic vendor. Especially when designing and building your own stuff.

As far as horse power goes. Don't forget the power used by the hydro and rear wheel drive motors.