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Hydraulic winch pump setup - Yet another one...


Tobias
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Right...

I have read all the threads I could find and here is where I stand.

I want to install a good sized set of pumps in my RRC to drive the MileMarker winch.

I reallt like the idea of having twin pumps, where both work at low preasure and only one at higher. This I expect will give a nice feedback on when the load increases as speed will drop and also improve control in high load conditions and reduce the power used to acceptable levels.

Right now I am trying to decide on Transfer box PTO or engine PTO and which pumps and motor coombo to go for.

In some circumstances I believe drive assist helps. it allows you to help steer a bit and also can help avoiding digging down in soft conditions, allowing you to "float" better.

For those that doesn't agree, the point of this post is not to argue over the possible merits of drive assista. If you don't agree with the possible merit, please just stay on topic if nothing else just to make sure the hydraulic part is understood.

The vehicle is a RRC, V8, TF727, LT230, Volvo C303 portal axles, Super Swamper TSL/SX 38.5

With a LT230 PTO the pumps will se the engine rpm less torque converter slip and initially the 2.45 first gear reduction in the TF727.

For the sake of argument, let's put the engine rpm at 2000 to minimise the torque converter slip and have the pumps spin at about 800 rpm.

The wheel will se a further reduction of 3.32 in the transfer box and 6 in the diffs, making them spin at about 40rpm.

Correct?

40rpm with 38.6 tires gives about 3m/revolution gives about 110m/min ground speed

twin group 2 pumps at 27cc would output about 45l/min.

Using a 100cc motor would give a winch drum rotation around 70 rpm and a line speed of 17-32m/min.

A factor of 3-5 difference in speed between wheels and winch.

The other option would be engine mounted pump. This would have to be crank driven as the power needed is too much for other solutions. I don't know if I have the space to fit the pump in front of the engine without moving the radiator.

Pump would see the full 2000rpm, giving about 100 l/min, giving about 180 rpm and line speed of 40-80m/min.

Somehow my calculations above doesn't feel right. I feel that I have too fast wheel movement for my rpms. Perhaps I'm right but I would like to have this confirmed.

Thanks

Tobias

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Don't forget if your running an engine pump you can always left foot brake to control your wheel speed with an auto gearbox.

I wouldn't get too hung up on the calculations as your usually in a wheel slip situation anyway. If you don't have lockers engaged then you usually end up with uneven speeds at the wheels so the speed the transfer box sees might not be what you expect.

I personally think if your going transfer box driven you should consider pto, if you can fit it in your saving the associated weight, heat and complication of the hydraulics.

The only problem with engine driven pumps on a V8 is they have a higher rev range than a diesel and your pump has to be comfortable working at that entire rev range, say 0-4000 rpm. If you gear for that what flow do you get at idle? Or 2000rpm?

Try and get teamidis attention, I believe he has a mile marker with an engine driven V8 pump.

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Engine powered is best IMO. I've seen it work and work very well, the biggest advantage IMO is you do with the gearbox/wheels what you want, you'll always have your winch.

If you can't fit the pump in front of the crank, a chain drive is also an option. Escape had this setup on his Td5 90, and except for a few issues with the clutch behind the pump sprocket, it worked very well.

Just remember to not overspeed the pump too much when the clutch is engaged. A big red warning light should do the trick for that. If you don't trust that enough, I'm sure that with Megasquirt you can change the rev limiter based on an input, which might be a good idea.

I'm not sure why you want the twin pumps though, the milemarker is already 2-speed and is plenty fast enough in high even with a tiny pump. I'd invest in an in-cab switch for the winch low/high before investing in a second pump (and the associated complexity).

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Attention gained :)

You don't need two speed pumps if you use a hand operated spool valve. There is no need to go slow unless you are at the end of the rope or in a tricky spot. Then you can go as slow as you like any time you want.

The milemarker motor already runs well over max speed, but you aren't driving a conveyer belt for 3 years so the extra wear per revolution is irrelevant.

The same isn't true for the pump. The life is less because a half worn pump won't winch and drive properly at low rpm. At full pressure the pump-leak-back is the same at any speed. At some point you overcome that loss via shaft speed and start winching. That's fair though, and it's why hydrostatic machines use axial piston rather than gear pumps like us lot :)

I run 80 litre a min at 3000 rpm.

I cut out the front crossmember with 3mm 50 X 100mm box below the rails. It mounts the skid plate stuff.

My pump is mechanically fixed to the engine, not the chassis. On a Serp engine you could be pretty short, even with the dog clutch? It depends on your flex coupling and crank adapter.

At 3000psi and 3000rpm it is over 30 HP?

If you are in the dry I would go belt and if it runs in deep mud I would go direct front PTO.

No argument from me on the work load. Front PTO is a real challenge to build :D

But it is oh so good to use ;)

Perfect set up?

Twin pump on front PTO to make two separate systems. One drives the winch, the other drives a motor in the transfer-box PTO hole for perfect winch-drive with good engine speed.

(My winch and drive engine speed is below 1500rpm engine)

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There are a number of pro's yo fitting to the crank, one that hasn't been mentioned is using the winch with gearbox in reverse. That's a major one for me.

We run a 33cc on the crank and I've got a PTO drive which I plan on putting a pair of probably 30cc pumps on. I'm not sold on the whole low pressure high flow argument due to the fact that you use a lever spool block. (I can only fit a group 2 on front due to space)

G

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Why with gearbox in reverse Zim?

A friend of mine is just fitting up a hydraulic setup to his 200TDi 110. After much deliberation he's sold his LT230 PTO pump and bought a modified tooth ebtl front pulley to replace the standard LR front pulley from Red Winches. He's bought a hydraulic winch to fit into a new custom bumper, but his primary use I think is going to be for ancillaries rather than winching. His 110 gets a lot of site use at our railway, one job looming is multiple concrete pouring jobs around site, so he's prepping for that. Having the ability to drive without loosing hydraulic at any point was one of the reasons for swapping over to engine rather than PTO, where dipping the clutch to change gear would have meant a loss of oil flow

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When reversing up an embankment, drive assist is very much appreciated. You'll end up breaking winch ropes as you put a hell of a lot of strain on them (either extra traction is needed, or you just end up squatting the vehicle etc). P.s. The OP only refers to one winch, but on the grand scale of things a second winch is not a lot more cost once you have the system in place.

The other one, which probably isn't good for the rope - is winch in on the front, spin wheels in reverse. Great for loosing traction and traversing sideways.

G

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Second winch makes sence if David Bouyer has any Kingone units left at £400 each. That's a great rear winch. Lower quality, bigger, but pulls as good as the milemarker. ( better on mine, as my front overrun valve is toss).

I think drive-assist is more important backward because it's harder to choose a good driving line. Some winch challenge punches would be out of reach without it.

I was accused of promoting twin pumps :D

I think that was to get around the oil pressure being shared between front and rear winches? With both going you only have 1500psi each. But I can't hardly remember yesterday. Plus I have no more space for a second stage.

I'll add a strange bit of info. I did say this in a PM to Tobias, but I'll throw it into the open pit;

Some guys had an electric tipper pump which they said was for self righting. However, I suspect it was more subtle than that?

A gear pump is 90% efficient or better. That 10% is what gets past the gears + drag. Lets assume it is all internal leakage...

So you do 100 litre a min internally at 3000rpm and 3000 psi and the gap lets through 10 litre/min. That mechanical leakage gap is the same regardless of pump speed, so you still leak 10 litre/min at 1000rpm. But your 90 litre/min output flow is now 33.3 minus 10 litre min. Add in some wear and you can't do full pressure at 1300rpm !

Unless of course, you have a booster device which isn't engine speed derived, like a 12volt tipper motor pump. I haven't the weight left to add anything else and I'm willing to put half worn pumps back on the shelf every 3 years, but its a neat fix. +you can self right if you set the oil tank up right.

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Thanks for all the great input.

Sorry for mistakenly saying Team Idris used two stage pumps, it was in fact 'aniesigh' who sold one about a year back and I got confused.

I haven't heard anyone critisising my calculations on wheel speed / line speed, which was really what I wanted to find out.

I will elaborate on why I feel dual-stage pumps or motors are a good thing, so that this can be discussed better.

I have only heard arguments pro-engine PTO driven pumps.

My winching experience is only to a very small extent Swedish style challenge events. Most of my winching has been recreational off roading where we have been using various cheap electric winches, Warn 8274, PS pump powered MileMarker and gearbox PTO powered on Scania SBA 4x4 military truck (11litre diesel and autobox)

The best drive assist of all is on the Scania. I have tried to look for the gearings to see how it is set up, but on that one it feels as if the wheels and the wire moves at almost the same speed.

Having experienced that and how well controlled the self-recovery feels with reasonably synchronised line speed and wheel speed was, is my motivation to at least try to get them close. I also like the way the autobox/torque converter makes the accelerator work as clutch/speed control, just as when driving with an autobox. For people who don't like autoboxes, don't start arguing for manual. I've made up my mind a long time ago which I prefer and installing a better pump system for my winch will not alter that.

The 8274 shines in the drive asisst department for exactly the opposite reason that the Scania also shines. Speed difference when loaded and unloaded.

When drive assisting with the 8274, the winch speed drops dramatically with load, wheel spins a lot and line moves slowly. As soon as the wheels get grip, the load decreases and line speed picks up, preventing a car with some temoporary traction from having to slow down too much to avoid over-running the wire.

Ideally I think I want the wire to move as fast or slightly faster than the wheels when unloaded and for drive assist and also power requirement, it can move slower, but no slower than half as fast as the wheels. Here is where the dual stage pumps come in. At low load, both provide flow and the winch line runs very fast. As load increases (pressure) one pump is bypassed and the speed drops, as well as power requirement. This would give the automatic line speed for tetrievel of the slack in the line when drive assisting wheels get a bit of traction.

So my calculation show a no-slip wheel speed of 118 m/min at 2000 rpm 1st gear low. With twin 63cc pumps and 80cc motor I would get a line speed of 50-100m/min depending on how much wire is on the drum. With Gearbox PTO, wheels and wire always more in unison, except when the transfer box is put in neutral. With engine PTO, as rpm decreases below torque converter stall speed, wheels slow down and stops wile the wire still moves.

A single 63cc pump at 2000rpm and 200 bar pulls about 42kw, the limit for the mechanical dog clutch I've seen is 40kw.

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