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Author Topic: Reversable hydraulic pump?  (Read 1278 times)

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Offline Satamax

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Reversable hydraulic pump?
« on: September 14, 2017, 05:45:57 am »
Since there's far cleverer people than me here.

I thought i would ask. Is there an hydraulic pump type. Of which the flow would remain the same ; regardless of rotation direction ?

Thanks a lot guys.
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb.

Offline Stuart Caruk

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Re: Reversable hydraulic pump?
« Reply #1 on: September 15, 2017, 01:38:02 am »
We build a hydraulic Payout winch for use in towing paragliders. It uses a gerotor style motor to mount the winch drum. In normal use the pilot is hooked to the line on the drum, and the drum Pays out line as the tow vehicle moves away. This pumps hydraulic fluid through a meter out circuit creating fluid flow that we control to maintain line tension. It makes no difference which way this pump/motor turns.

Your problem will be figuring out how to control the fluid flow into and out of the pump. You're going to need to swap both ports over each time you change the pumps rotation direction.
Stuart Caruk
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Offline Satamax

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Re: Reversable hydraulic pump?
« Reply #2 on: September 15, 2017, 03:26:17 am »
Thanks a lot for your reply Stuart.

Found the answer. Piston pumps, with valves, either inline or radial. Are able to turn both ways, with the flow always in the same direction.
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb.

Offline Riwaka

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Re: Reversable hydraulic pump?
« Reply #3 on: September 15, 2017, 08:09:00 am »
If the hydraulic pump is winch related..... there are hydraulic logging spec winches with a 'power out' function  used on ' tong tossers' , so you are not having to pull the weight of the cable on the winch drum.
http://www.brevinipowertransmission.com/en/prodotto/winch-drives-en/      (somewhere in a brevini catalogue)

Offline mike_belben

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Re: Reversable hydraulic pump?
« Reply #4 on: September 15, 2017, 10:27:14 pm »
Yes, a variable displacement piston pump is one half of your typical hydrostatic drive.  Tilt swashplate one way or the other to change flow volume and direction.

If you had tennant sweepers in your country, those had a single hydrostatic pump for the main drive.   Skidsteers use one per side in tandem.  Some tractors, trenchers, cable plows etc

Offline kiko

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Re: Reversable hydraulic pump?
« Reply #5 on: September 16, 2017, 08:16:41 am »
With a variable displacement pump in a hydrostatic system, the charge pump would have to be the set up for a left or right hand input rotation.   It will take a lot of explanation for me to understand how any pump could work the same on a left and right rotation. But,. I am always open to new knowledge.   Many pumps can be set up  for left hand. OR. right hand rotation.  May be I misunderstood the OPs question.

Offline mike_belben

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Re: Reversable hydraulic pump?
« Reply #6 on: September 16, 2017, 11:10:30 am »
Wait a minute .. You want to reverse the pump input shaft rotation and get the same output? Like run a gear pump off a reversing pto shaft? 

No.. Cant do that.  Your suction side would become your pressure side and charge your reservoir.  If you managed to plumb it into some wierd loop and actually build pressure the  it would blow the shaft seal out of the pump.  When you look at a gear pump  "3" seal youll note that pressure side is blocked from the lube passages to the bearing and seal.  I supercharged a gear pump off the implement lift circuit of a garden tractor hydro once.  More than about 10psi into the pump inlet pushed the seal out every time.  You cant make the input become your output.


I was picturing a drivemotor for a winch to power in and out. That would essentially be a hydrostatic trans.  Charge pump + variable piston pump spinning constant direction, outputs to a hydro motor than can spin both directions to power winch in and out. 

Youve gotta take power off your crank, cam, or first transmission's input shaft. The rest reverses.

Online Gary_C

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Re: Reversable hydraulic pump?
« Reply #7 on: September 16, 2017, 11:11:41 am »
With a variable displacement pump in a hydrostatic system, the charge pump would have to be the set up for a left or right hand input rotation.   It will take a lot of explanation for me to understand how any pump could work the same on a left and right rotation.

I agree. Hydraulic motors are routinely run in both directions but not the pump.
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Offline Satamax

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Re: Reversable hydraulic pump?
« Reply #8 on: September 16, 2017, 02:20:14 pm »
Mike.

I have checked on an engineering site, called "usinages"

And the guys say, some old piston pumps are reversible. Would they be inline, or radial. These are valved hydraulic pumps. And that's why the work both ways.

I have no choice. If i want to use the transfert case PTO. I face the problem of reverse gear useage, while driving. So the pump will be reversed. And i dont want to do something with automatic disengage. Which would make me loose the hydraulic power.

Guys, if ever someone could tell me which brand is this one.

I would be very thankful.


 Bears a number V21-75-5947

and 75-210
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb.

Offline Satamax

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Re: Reversable hydraulic pump?
« Reply #9 on: September 16, 2017, 02:31:35 pm »
Thanks a lot for all your replies guys.

Here's a youtube explanation on how these work.

French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb.

Offline Autocar

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Re: Reversable hydraulic pump?
« Reply #10 on: September 16, 2017, 06:34:02 pm »
I have a gear pump in the shop I used on a 110 Prentice and it is a right and left rotation eather or.
Bill

Offline Oliver05262

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Re: Reversable hydraulic pump?
« Reply #11 on: September 16, 2017, 10:55:48 pm »
  Satamax, the radial piston pump has been used for years on John Deere farm tractors. It is the main pump, which is mounted in front of the engine on tractors from 1960 onward. Look up the pump on a 2840, 4240, or a similar tractor. A pump such as these would work while rotating in either direction, but it cannot pick up suction from a reservoir. It needs to be supplied by pressurized oil from another pump, usually a gear pump. A gear pump would need to have the suction and discharge ports reversed each time rotation direction changed.
  As was stated, if you were driving a motor with the pressure oil, such as if you were running a winch in either direction, you could use a variable displacement axial piston motor. These can reverse direction by moving the swash plate, which acts as a rotary valve, and will internally change the output shaft rotation direction. In this way, your engine driven pump would always turn the same way, and send oil out in the same direction. Changes would be in the motor.
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Offline kiko

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Re: Reversable hydraulic pump?
« Reply #12 on: September 17, 2017, 12:55:43 am »
So, from the cumulative knowledge of the forestry forum,. Satamax needs a radial piston pump running off the transfer case pto and the charge pump running off the engine with a belt drive if no accessory drive exist on the engine.

Offline Satamax

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Re: Reversable hydraulic pump?
« Reply #13 on: September 17, 2017, 03:39:18 am »
  Satamax, the radial piston pump has been used for years on John Deere farm tractors. It is the main pump, which is mounted in front of the engine on tractors from 1960 onward. Look up the pump on a 2840, 4240, or a similar tractor. A pump such as these would work while rotating in either direction, but it cannot pick up suction from a reservoir. It needs to be supplied by pressurized oil from another pump, usually a gear pump. A gear pump would need to have the suction and discharge ports reversed each time rotation direction changed.
  As was stated, if you were driving a motor with the pressure oil, such as if you were running a winch in either direction, you could use a variable displacement axial piston motor. These can reverse direction by moving the swash plate, which acts as a rotary valve, and will internally change the output shaft rotation direction. In this way, your engine driven pump would always turn the same way, and send oil out in the same direction. Changes would be in the motor.

Oliver. This is all complication. This is not a normal tractor, but a 4 equal wheel forestry tractor. Made in France, from Saviem/renault military truck parts.

The forward and reverse of the winch  would be actuated by a distributor. As simple as this.

But the problem i have is:

I can't run the pump from the gearbox end PTO. Too expensive a PTO. Not much room for a big pump.

I have found a normal under the gearbox PTO, with pump. But the pump is small ish.

Edbro brand from what i can gather. But i don't know either flow nor pressure.




So what option is left? Use the transfer case PTO, which, when i use the reverse gear of the gearbox, would turn in the wrong way for most pumps.

Why i look at piston pumps in general.


And thousand times sorry. Your explanation of one pump feeding the other seems very weird to me. Ok, it might work like this on a deere. But Why would you put two pumps in series, Just augment the pressure?

 
So, from the cumulative knowledge of the forestry forum,. Satamax needs a radial piston pump running off the transfer case pto and the charge pump running off the engine with a belt drive if no accessory drive exist on the engine.

Kiko, this seems like unnecessary complication. With the room i have, i could fit a double V groove, or 1.5" toothed pulley. Maximum power i can transfer this way. 7kw. Approximately. No more.  So i need to find a monster pump, taken on the T case, which can self feed, and be reversed in rotation, but not flow.


Thanks a lot guys, for all your replies.
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb.

Offline Satamax

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Re: Reversable hydraulic pump?
« Reply #14 on: September 17, 2017, 04:13:03 am »
Hi everybody.

Well, checked again. "Check valve" or "pintle valve" pumps seem to be reversible, and they don't seem to need pre charge.
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb.

Offline snowstorm

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Re: Reversable hydraulic pump?
« Reply #15 on: September 17, 2017, 07:31:02 am »
why not run the pto on the main trans? or run the pump off the engine. either belt or direct from the crank. i have several class 7 and 8 plow trucks. they all run off the crank. some with gear pumps some piston. and a f550 with a belt drive. there are at least 2 outfits that make belt drive kits for just about anything with a motor. c w mill equipment is one of them??

Offline mike_belben

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Re: Reversable hydraulic pump?
« Reply #16 on: September 17, 2017, 10:36:29 am »
The swash plate piston pumps i know of require charge pressure or theyll burn up.. About 100psi worth.  So im pretty confident youre going to need a single direction pump off the engine or input shaft end of trans no matter what you do.  Why bother rigging up a gear charge pump to feed a variable displacement pump off the pto?  Im with snowstorm. Just find a way to rig a suitable gear pump off the engine, to a control valve that feeds a motor on the winch.  You can use a closed center log splitter valve with a detent in one direction for spooling line out while you pull cable to the choker.  A belt driven 12v clutch central hydraulic pump is about $600 and a splitter valve new is around $100 usd.  Surpluscenter.com


Offline mike_belben

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Re: Reversable hydraulic pump?
« Reply #17 on: September 17, 2017, 10:39:32 am »
Btw, this reversing pto you want to couple to... Is it a ground speed or crank speed pto?

Offline coalsmok

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Re: Reversable hydraulic pump?
« Reply #18 on: September 17, 2017, 10:55:08 am »
I have a lathe with a pump on it that works the way you are wanting. It is a small pump and was $400 last time I checked on a replacement. Can't imagine what one big enough for a skidder would cost you.

Offline Satamax

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Re: Reversable hydraulic pump?
« Reply #19 on: September 17, 2017, 05:38:29 pm »
why not run the pto on the main trans? or run the pump off the engine. either belt or direct from the crank. i have several class 7 and 8 plow trucks. they all run off the crank. some with gear pumps some piston. and a f550 with a belt drive. there are at least 2 outfits that make belt drive kits for just about anything with a motor. c w mill equipment is one of them??

Snowstorm, i can't run on the main trans, if i want a big gpm pump, i don't have the room.  If oit's on the top PTO. Top PTO is next to the drive-shaft going from gearbox to transfer case. And this one is complicated to use, as the arbor there is of an unknown type. I can get military parts, but these are extremely expensive. 

For the bottom of the gearbox PTO, i have found one. With the unknown edbro piston pump. Don't know if it's a sae flange or whatnot. I would like to know what i will get before i buy it. Hence my search for informations.

Crankshaft, i can't, i don't have the clearance. There's the radiator in front, and the fixed fan. So the best i can fit is two A type belts. 6 kw transmission, or may be 7 with a toothed belt. That won't work for a winch.  And i can't use a shaft on the pulley, as the radiator goes past the bottom of the crankshaft pulley.

So, what is left, transfer case PTO.

Btw, this reversing pto you want to couple to... Is it a ground speed or crank speed pto?

Mike, i should say i'm not familiar with those terms.  Crank speed PTO, well i guess. Since the speed of the crankshaft goes the through the gearbox.

So i have a selection of 5 speeds and a reverse.

7.41/1 for the first, so that would be 94 rpm for 700 rpm idle.

167 at 4.19/1 for the second gear.

292.88 at 2.39/1 for the third

472.97 at 1.48/1 for the fourth gear Close to tractor PTO.

700 for the fifth gear which is 1/1

This is for an idle of 700rpm. Which i don't know if it's that.

This is why i would need a big gpm pump. so i don't loose the hydraulic pressure on the low gears.

In fifth at 1500 or 2000 rpm, i have no problem. But i might need to use the blade on a descent, at low gears, and if i don't have a smidge of hydraulic power. That's no good.

Thanks a lot guys, for all of your replies.
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb.