Sizing hydrualic motor
Posted July 17, 2010 - 12:04 AM
Now that i have seen the math behind your words, i see how this will work much better. If i use an auto tranny, then it already has reverse, so the valve would just need to make it stop, go, and change speed within gears. Also, could i get the tractor up to 10 mph, so its a little bit faster than my other GTs? My thinking was i could slow it down but shifting the tranny, and still move the tractor around the yard a tad faster than the others.
Thanks for all the help, i knew there was a good reason i liked these forums.
Posted July 17, 2010 - 08:07 AM
If you ask an architect to design a house for you and after he does so, you then tell him that you want a 2nd story put on it, then do you understand where I'm going with this?
You should have disclosed at the outset several things such as,
1. I'm putting a loader on this tractor.
2. I'm putting a 3 pt on this tractor.
3. The pump I have is actually a 2 section pump.
All of that information affects the way your system will be constructed. I don't mind trying to help but please....don't expect me or anyone else to work in a vacuum.
Once again, I have great concerns over this pump you have because it is the very item that is at the center of every calculation. The pump size is dictating the motor size, the cooler size, the reservoir size, the hose sizes and the valve sizes. It also dictates the size of engine that is selected to drive that pump. IF........you are correct and this pump has two sections that will put out 17 gpm for a total of 34 gpm, then the math says you need 40 hp to produce 34 gpm and 2000 psi. If you don't have adequate hp to spin a certain pump, then the engine just stops dead in its tracks whenever the system asks for 34 gpm at 2000 psi. It's like trying to pull a heavy load up a steep hill from a standstill using 4th gear in a 4 speed transmission.
Moving now to your statement " If i use an auto tranny".
You need to get a grip here. That isn't happening and the reasons why it isn't happening are plentiful. Find a small transmission from a car that is either a 3 speed or 4 speed. The smaller the better, physically. Don't worry about strength. That isn't an issue and never will be. This is about keeping it compact.
Yes, it is possible to raise the target ground speed to 10 mph but I think you need to verify the gpm of this pump prior to proceeding any further. If need be, take it to a hydraulics shop and ask them to pinpoint what you have. Until we know to an absolute certainty what each section of this pump is putting out, everything is just a waste of time.
Posted July 17, 2010 - 08:41 AM
Posted July 17, 2010 - 10:34 AM
I "think" he means a std shift tranny from an "auto", not an automatic trans.
Dan, I believe you are likely right. However, I certainly need clarification about this pump.
Posted July 17, 2010 - 10:34 AM
Alright, so now i should be looking for a hydrualics shop to find the displacement of the pumps. Then we can all know for sure what we are working with.
Oh, and the tires are 98 3/8 inches in circumference.
Posted July 17, 2010 - 11:00 AM
Posted July 17, 2010 - 12:03 PM
Posted July 18, 2010 - 08:47 PM
Posted July 19, 2010 - 08:02 AM
If you knew the VIN from the donor vehicle plus the make, then a check at the local dealer's parts department would answer this question. Short of that, opening up the center section and counting teeth or discovering numbers stamped into the edge of the ring gear is the only other option. I'm sure you realize that accuracy is needed if you wish to end up with a tractor that performs the way you want it to.
Posted July 19, 2010 - 06:56 PM
Posted August 04, 2010 - 09:17 PM
Posted August 05, 2010 - 08:51 PM
Posted August 06, 2010 - 09:46 PM
Posted August 09, 2010 - 03:00 PM