Keep Hydraulic System @ Rated RPM

3RRL · Jun 5, 2006

One thing I noticed (specifically on my tractor) is that the power steering, loader and 3pt love and need rpm to perform at their best. Is this common for all Chinese tractors or any CUT tractor for that matter? I imagine the large industrial machines already have this feature? I'd like to figure out a way to over come this (slight) design oversight so I can run my tractor within the maximum torque range (when I don't need to make more horsepower) without having to rev up the rpm so my hydraulics work better. On my tractor, the maximum torque is developed well below the maximum rpm.

Has anyone thought about having a variable multiplier to drive the hydraulic pumps, turning them at rated rpm speed regardless whether the engine is at idle or running full blast? I imagine this device as being a sort of CVT concept only operating in reverse. In other words, when the engine is at 600rpm idle, this coupler/multiplier contraption is causing the hydraulic pumps to function as though the engine is running at rated rpm. And when you increase the engine rpm the hydraulic pump continues to function the same...regarless of the engine rpm.

Now, I don't know enough about tractor hydraulics or what's available for hydraulics in general so I'm asking. Is there anything out there already like a hydraulic system supercharger or would something like an accumulator or larger pumps, more hydraulic flow any attachments or something that will do similar to what I want?

3RRL · Jun 5, 2006

One thing I noticed (specifically on my tractor) is that the power steering, loader and 3pt love and need rpm to perform at their best. Is this common for all Chinese tractors or any CUT tractor for that matter? I imagine the large industrial machines already have this feature? I'd like to figure out a way to over come this (slight) design oversight so I can run my tractor within the maximum torque range (when I don't need to make more horsepower) without having to rev up the rpm so my hydraulics work better. On my tractor, the maximum torque is developed well below the maximum rpm.

Has anyone thought about having a variable multiplier to drive the hydraulic pumps, turning them at rated rpm speed regardless whether the engine is at idle or running full blast? I imagine this device as being a sort of CVT concept only operating in reverse. In other words, when the engine is at 600rpm idle, this coupler/multiplier contraption is causing the hydraulic pumps to function as though the engine is running at rated rpm. And when you increase the engine rpm the hydraulic pump continues to function the same...regarless of the engine rpm.

Now, I don't know enough about tractor hydraulics or what's available for hydraulics in general so I'm asking. Is there anything out there already like a hydraulic system supercharger or would something like an accumulator or larger pumps, more hydraulic flow any attachments or something that will do similar to what I want?

Soundguy · Jun 5, 2006

You are overthinking the issue here... Tractor pumps are usually positive displacement variety... lower rpm yeilds lower output... just works like that.

If you needed a high output at low rpm.. you would be better served with a multi staged pump or one with a higher displacement, and then just 'dump' the oil not used thru the open center system... Mind you.. you have to understand that a pump uses hp... If you are at low rpm.. there is less hp available to the pump... also.. the tractors pump drive will only be rated for so much hp.. thus you may not be able to upgrade much from stock.

Some peopl eadd aux belt pumps.. dedicated ps systems.. etc.. or pto pumps for high volume situations.. etc.

Soundguy

Soundguy · Jun 5, 2006

You are overthinking the issue here... Tractor pumps are usually positive displacement variety... lower rpm yeilds lower output... just works like that.

If you needed a high output at low rpm.. you would be better served with a multi staged pump or one with a higher displacement, and then just 'dump' the oil not used thru the open center system... Mind you.. you have to understand that a pump uses hp... If you are at low rpm.. there is less hp available to the pump... also.. the tractors pump drive will only be rated for so much hp.. thus you may not be able to upgrade much from stock.

Some peopl eadd aux belt pumps.. dedicated ps systems.. etc.. or pto pumps for high volume situations.. etc.

Soundguy

JerryG · Jun 5, 2006

You will notice this problem more on older Japanese compacts than the new one. It is still present, but has been reduced because of the installation on higher gpm pumps. As more and more speed has been demand by customers and also the desire to drive move hydraulic implements, larger pumps have been installed. The last time I looked at the specs for a Chinese tractor the gpm was on the low side. I am sure in time as the Chinese become more familiar with the American market they will also increase the size of their pumps.

JerryG · Jun 5, 2006

You will notice this problem more on older Japanese compacts than the new one. It is still present, but has been reduced because of the installation on higher gpm pumps. As more and more speed has been demand by customers and also the desire to drive move hydraulic implements, larger pumps have been installed. The last time I looked at the specs for a Chinese tractor the gpm was on the low side. I am sure in time as the Chinese become more familiar with the American market they will also increase the size of their pumps.

slaveToHorses · Jun 5, 2006

even my 60hp large utility tractor wants some revs to lift a heavy implement.
"It's just the way it is"

slaveToHorses · Jun 5, 2006

even my 60hp large utility tractor wants some revs to lift a heavy implement.
"It's just the way it is"

dfkrug · Jun 8, 2006

I agree with Jerry....you prob have a low-flow pump. What
is the rating and how many pumps does the tractor have?
My guess is one pump for both the implements and the PS.

A two stage pump would be nice. This is what log splitters
have. You get high flow when pressure is low, and low flow
when you need the pressure, esp when your splitter has only
a 5hp motor. Variable-displacement pumps are prob
what industrial machines have. I noticed when operating an
excavator that the carriage would turn faster if I held the lever
in that position more than a second or so.

dfkrug · Jun 8, 2006

I agree with Jerry....you prob have a low-flow pump. What
is the rating and how many pumps does the tractor have?
My guess is one pump for both the implements and the PS.

A two stage pump would be nice. This is what log splitters
have. You get high flow when pressure is low, and low flow
when you need the pressure, esp when your splitter has only
a 5hp motor. Variable-displacement pumps are prob
what industrial machines have. I noticed when operating an
excavator that the carriage would turn faster if I held the lever
in that position more than a second or so.

3RRL · Jun 8, 2006

The KAMA 554 has 2 pumps...one separate for the power steering. That is really the one I'm interested in reving up. Under normal loader use when transporting dirt in the bucket, I cruise to the spot for dumping and sometimes the power steering does not react unless I crank up the rpm's.

My question was to see if
1) it is possible to change to a higher flow?
2) if there is something out there already?
3) keep it simple?
4) or not worth it?..just increase the rpm's? (obvious solution, ha ha)

Thanks,

3RRL · Jun 8, 2006

The KAMA 554 has 2 pumps...one separate for the power steering. That is really the one I'm interested in reving up. Under normal loader use when transporting dirt in the bucket, I cruise to the spot for dumping and sometimes the power steering does not react unless I crank up the rpm's.

My question was to see if
1) it is possible to change to a higher flow?
2) if there is something out there already?
3) keep it simple?
4) or not worth it?..just increase the rpm's? (obvious solution, ha ha)

Thanks,

Soundguy · Jun 8, 2006

I'd look for a higher capacity pump... the excess oil is just dumped anyway..

Soundguy

Soundguy · Jun 8, 2006

I'd look for a higher capacity pump... the excess oil is just dumped anyway..

Soundguy

theonlybull · Jun 13, 2006

it's mostly the way things are, unless you wanna spend gobs of money, on a system that's gonna take alot of room, alot of plumbing, and may have some odd quirks. some excivators and new equipment have varriable displacement pumps, and presure compensated systems, but they are $$$ equipment, and built for a guy who's running them 10-12 hours a day.

our 580 case, although an older machine has the same thing. if you want more power to steer, or faster loader travel, you shove in the clutch, and rev it up.

if its your steering. have you tried putting some weight on the 3pt hitch when doin loader work? it'll take some of the load off the front, and allow it to steer easier.

slaveToHorses · Jun 13, 2006

That's where hydrostatic transmissions really shine. The ground speed is independant of engine speed (except for maximum speed of course).

Soundguy · Jun 15, 2006

However.. PTO speed is still ratio-locked with the engine speed...

Soundguy

GEB · Jun 27, 2006

I would look into changing JUST the pully on the pump.
Surely you can find one to fit or make one fit.
You'll need to go smaller, just a little smaller than stock.
Gene

3RRL · Jun 27, 2006

GEB said:
I would look into changing JUST the pully on the pump.
Surely you can find one to fit or make one fit.
You'll need to go smaller, just a little smaller than stock.
Gene

Well,
I looked in the parts manual and it appears that my pump(s) are gear driven. But you have given me an idea. Now I'll need to check if spinning the OEM pump faster will hurt it?
Thanks,

schmism · Jul 27, 2006

3RRL said:
Well,
Now I'll need to check if spinning the OEM pump faster will hurt it?
Thanks,

Thats what i would be conserned with. If it spins close to "normal" speed after you modifiy it at only 1500 (engine) rpm then it might over rev and cavatate at higher engine rpm.