Hydraulic winch on GQ Patrol - line speeds

I run a Nissan Patrol PTO gearbox close coupled to a hydraulic pump, that powers my Milemarker 15000lb hydraulic winch. I have recently purchased a 3:1 planetary gearbox to increase the output speed of the PTO box and hence get greater flow to the pump and then winch motor.

Below is the data I have discovered and the results regards line speed. The PTO is nominally rated at 18kw.

The Nissan PTO has two fixed ratios, forward is 1180rpm for 1000rpm engine speed, and reverse is 1530rpm for 1000rpm engine speed. The nissan PTO runs off the gearbox, unlike the Toyota that runs off the PTO. This design is limiting as to increase line speed you have to increase engine speed as opposed to selecting a different ratio or gear on the Toyota. This limiting factor is the reason I am soon to upgrade the drive speed to the hydraulic pump by a ratio of 3:1 using a suitably sized planetary gearbox running in reverse.

The hydraulic pump is rated at 0.032L/rev. At the existing setup and at engine idel speed of 500rpm, the pump runs at 554rpm, and delivers 17.73lpm to the winch motor. Based on the first drum circumference and Milemarker specs, this results in a slow speed retrieve speed of 3.6m/min. This speed does increase as the drum diameter increases, and does not affect the loading detrimentally due to its design capacity.

The new speed will be 3 times this, so approx 10.5m/min at 500rpm engine idle speed. Increasing the engine speed directly increases line speed, hence I will need to do a slight change in hose size to uprate for the increased flowrates. I have not checked this out fully however suspect the pressure line will uncrease from 3/8" to 1/2" and the return to either 5/8" or 3/4".

WOW will be a beast mate. How much line speed loss under load?

Thank christ for that old mate, looking forward to seeing this in action!

Last time I saw you winching I fell asleep!!!

You have some serious projects to do under your belt mate, looking forward to seeing it come to life!

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Originally Posted by MudRunnerTD

WOW will be a beast mate. How much line speed loss under load?

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It should not slow down under load. Hydraulics is best described as 'liquid steel'. As long as you have the HP to generate the flowrate, and the pressure, its go go go. Plus, if I switch from low speed to high speed, yes higher again, however the load rating plummets to a 1/4 of low speed rating. I will however need to also increase the oil reservoir capacity and may need a larger oil cooler. If its 'too fast' I can always throttle it back a bit.

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Originally Posted by AB

Thank christ for that old mate, looking forward to seeing this in action!

Last time I saw you winching I fell asleep!!!

You have some serious projects to do under your belt mate, looking forward to seeing it come to life!

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Yep, the beast is growing some limbs for sure. Have not broached the subject yet about starting the jobs with 'you know who', as its going to be a 2 month activity due to the restrictions with rosters and time away from home. Best thing though is that all the bits are here except the driveshaft assy for the pump. The area is very tight between the gearbox and the driveshaft, so I will need to run a shaft down to the start of the rear muffler region to fit it in, which then requires brackets and plates etc etc.

Hahahaha. There is plenty of room Phil!!!.....

Wait? Was thinking of a different car! Yeah, Nah, your stuffed.

How much pressure does your system run? If your current system runs say at 100Bar then you will need 3kw at 17LPM. If you want to run 50LPM then you will need 9kw of power. If the pressure is around 150 bar then you will need 13kw of power. What type of hydraulic pump and motor are you utilising?

With hydraulic motors you normally get higher speeds with a smaller motor but less torque. Go to a bigger motor you get less speed but more torque.

Its a 32cc/rev pump, gear style, and think the same style on the winch, pump rated at max 3000psi, have pressure relief set at 2300psi,(winch rated to 4000psi) max speed 2000rpm, its run at 1500rpm under a pull up a steep rocky track and never went out over the pressure relief valve, temp runs out at around 100degC on the oil before I put the oil cooler in place and increased reservoir capacity, now oil doesnt get much over 65 - 70 degC - can pull all day at this rate, have actually used it on a recovery that was a constant 6 hrs duration, 20m pull one after the other up a track as slippery as glass. The pump is used on garbage trucks I believe so its a tough bugger. Room is very tight - took me a while to find this one ex UK. Only potential areas of concern are the driveline alignment as the pump or pump and gearbox have to be relocated further down the vehicle. I would have liked a 60cc pump however the physical size knocked it out of consideration. This one works well for me, did have a belt driven pump running off a veebelt off front of engine before this one and it was around the same capacity. Oil reservoir will need to go up, currently sitting at 8 litres. Very infrequently used so duty cycle is low but intense. I like the gear style for its simplicity.

Ok so your running at around 165 Bar which requires just over 13kw. So lets say 14kw requirement. This is if I have calculated your pump rpm right (approx 1500rpm) which will be putting out 48LPM at that rpm. Do you know the displacement of the hydraulic gear motor?

Very good that you put the cooler on as you do not want hydraulic oil exceeding 70 degrees. You will have to watch the valving though as the flow increase could be to much for current valving and have it going across the relief more. This will obviously cost you power and create unwanted heat. I would be trying to triple that oil capacity at a minimum if there are gonna be times like you describe above. Driveline alignment can be negated by using a standoff for the pump. So a seperate bearing housing taking the load instead of the pump.

Motor spec says 220cc, so I get a revised line speed of 48000/220=218rpm x 0.234m circ of winch drum = 35.7m/min. Gearbox ratio on winch is 5:1, 7.14m/min, so still quick enough - I think this is correct, but pump speed is now going to be circa 1770 due to the PTO ratio instead of 1500, so roll up to circa 8.5m/min instead of 10.

If what you say is true and you dont go over relief then you could also use a slightly smaller motor to increase winch speed as well. You currently have just over 900nm available with you current setup at the moment. If you dont need this much then you could do as above.
You could sacrifice some torque in favour of speed then if required just double the line pull.

Bit of an update, new PTO hyd pump set up runs at 525rpm and 575rpm depending on PTO position selected. I am running a 70cc pump to drive either a front or rear winch. The front is a 15000lb milemarker and the rear a 20000lb winchmax. The line speed is more than adequate, faster on the front but suspect this is due to the different gearbox ratios. I am waiting on the pressure gauge setup to set the system limits. First observations are very encouraging to say the least. I looked at the speed increasing gearbox route but became too much of a beast to set up.Attachment 87144