DIY Hyd Pump

[td9clyde]

small simple and high presure and something easy to get parts for if that would help

[trucker n]

i would be interested in testing pumps would be nice if they had the tank with then i think running on 55t motor would be fine i run mine on 11.1 v lipo

[doodlebug]

Hey pugs, is there a hobby motor out there that's rated for continous duty? That seem's to be the "kicker" with a few of the readily available unit's. Or some sort of heatsink to add on to the motor?
Later, Neil#2 aka doodlebug

[Lil Giants]

These 55, 65, ect turn motors that the truckers always refer too are the Integy 12v lathe motors that they are running on 7.2v? Does anybody have any relevant data on them?

I think it's a Johnson motor on the Leimbach pump. @13v, 6000rpm freespin @ 1.1amp, approx 4000rpm full load (flow thru the relief valve) @ 2.2amp (I've measured the amp draw myself @15bar pressure).

The only problem I have ever had is oil leaking past the input shaft & into the electric motor that drives it... eventually (20-25 start ups) the oil burns out the motor. It's only a few drops while it sits long periods between use (few days or wks). And yet, I have one Leimbach pump 10yrs old/over 1000hrs that continues to work fine... go figure. Definitely need to have a seal on the input driveshaft. Damitz pumps have one, I've never heard of one failing yet.

The preferable voltage would be 10 cells, 12v (13.5 to 14 @ full charge), though lipos are becoming more & more popular all the time... I'm gonna try lipo with my 850 to start with. Maybe 3s @11.1v or 4s @14.8v but with a Castle voltage regulator set to 13v constant.

Leimbach, as an example, running the pump too fast will disengrate it in short order. Width of the gears determines the oil flow moreso than the diameter. 2.5mm to 3mm dia plumbing with a pump output of 350 to 400ml/min is plenty for 14th scale hyds.

[td9clyde]

yea ok heres the thing not all of us run in 1/14 th scale here Joe hopefully as you have seen there is alot other models that are bigger and some are smaller if there was a little bit higher preshure pump around the same size as the pumps used in 1/14th scale models it could be used for 1/14th and bigger to me honestly so far what i have seen is that the hydralics thus far is slow it is hard to build a model that works like it should if it makes you mad everytime you run it cuz it is slow real time is hard to distinguish scale time/or speeds why not use a drill motor with the planetaries?not high speed but has torque most to real hydralic pumps run at 2200 rpm's at the most on equipment and some are less

(The only problem I have ever had is oil leaking past the input shaft & into the electric motor that drives it)

if that was the main problem why not put in a weep hole so it will drain between the two parts there is alot of varibles with pumps and preshures just my two cents

[pugs]

Ok, starting to get an idea of what you guys want in a pump (or pumps). I'm trying to find a good motor that would be a bit slower rpm which would help everything last a bit longer and getting some info from my seal supplier on what is available for the small stuff. The pump I have here does have a shaft seal in it, but is difficult to replace might be something I try and address with a new design.

[steamer]

Joe. Just to let you know there are three seals on the input shaft on the leimbach pumps. Next time you have one apart have a look behind the drive plate on the pump. One setscrew will remove it. There you will find a bushing with four center punch marks. When I repaired the one I did I drilled out the punch marks and put two 1/16 role pins in the head to get it out, There you'll find three o'rings one in the pump body and two in the head. The reason the leak is they used cheap rings instead of Viton. The other thing you'll find if you look at the gears in the pump is it's steel gears running strait on the aluminum body. I think the gears should have been bronze or brass and you wouldn't be getting the dirty oil. The blackness is the gears chewing up the aluminum body of the pump. The higher pressure will make it worse. I think if a person made up some .010 brass inserts for both sides of the gears would improve it greatly and increase the life of the pump.
Rob

[Lil Giants]

So whatcha figure Henry, the best bang for Jeff's $ would be to build a pump that caters to the 2% scale you build in or the 80% that build in 14th. Kidding aside , it's not that you need high pressure, just higher flow. The majority of pmd's stock in the past has been 1.5mm hose & fittings between the valve(s) & cylinders.

With my newer Stahl Komatsu loader & Liebherr excavator, both these models have 2.5mm plumbing throughout the hyd system & I'd say it's near triple the speed of cyl cycles.

In your case of 10th scale, I'm sure a 350ml pump will easily handle 3mm plumbing, maybe even 4mm, but that could be stretching it's capabilities with pressure fluctuation.

The kind of pressure you seem to think you need to have would be like my 850 hoe, and this hyd system is freaking huge & expensive! Did you look at Ole's & Kalle's build threads on Scale4x4 that I linked to when I 1st show my 850 build? Approx area for pump, brushless motor, reservior, up to 4 valves = 9x4x4 inches. Will that fit in your Terex or Caterpillar? That's a Jung pump & I'm only guessing here, approx flow 500ml/min @25 bar recommended.
http://i172.photobucket.com/albums/w...0/DSC07142.jpg

Hmmm, I never dove that far into taking the Leimbach pump completely apart. I saw the bronze bushing behind the drive gear... just assumed the seal relied totally on tight tolerances. Learn something new everyday. Thanx for the insight Rob & Jeff.

Though I wonder about the comment of the steel gears chewing up the aluminum body... if the tight tolerance is lost between the top & bottom of the gears, then the oil would no longer flow only around the outside of the gears to make pressure. Right? I've never had a pump loose pressure. It's my belief that the oil darkens mainly b/c of the aluminum cylinder barrels... once we get our hands on stainless steel barreled cyls, the proof will be in the pudding.

[pugs]

Well if all works as I'm hoping it wouldn't be long after getting the first pump designed, I'd look into a slightly larger version.

Would brushless motors be preferred over brushed? I haven't kept up to date on the motors the last few years, I know the brushless cost more, but do they also need a fancier esc to run them? Maybe a pump design with a cheaper base brushed motor and upgradeable to brushless is a better route?

Again thx for the info all, don't want to start any wars between what is better this scale or this one etc, just trying to find out what is wanted in a pump and whats wrong if anything of the current offerings.

[steamer]

I've got the pump back that I put the new seals in to do an auto cad drawing for the gear side shims. I'll try and get some pictures of the way the face looks inside the pump and they way the gears are worn on the end of the teeth. You would probably would never notice a loss in pressure, because I'm sure if you kept closing the pressure relief valve this pump would keep going up till it stalled the motor and that just the way a gear pump is. That why they burn out the motors on the UMS pumps because when you hit the end of stroke it's full stall. I'm sure if they had a PR they would be fine. Inside it's the same as the other pump but they use bronze gears instead, so you don't see the same scratch marks. With the side area of the gear greater than the width, higher pressure forces the gear tighter to the face causing the damage and the aluminum shavings in the oil.
Rob

[steamer]

Have some pictures of the body head and gears of this pump. You'll see what I mean from the gear side pressure and it's about .010 deep. The one with the deepest undercut is the driven one. Picture of the gear was hard to focus on but you can see the curl on the trailing edge of the gear. Don't know if that is wear or pressure build up between the gears. If they're not made right and the mesh is too tight, they build pressure just coming together, IE trapped oil. These are good pumps and I think with a few changes they could be made better.



Rob

[RCLogger]

I keep telling Rob that he should open up a rebuild shop as he has redone two of my pumps and they are like new again. No more oil leaking through to the electric motor.
Great work figuring out these pumps Rob

greg

[doodlebug]

Hi guy's, what if the pump could have more section's (stacked) added to it for larger scale, and keep most of the part's common? Would that help you Henry and keep the cost down? http://www.surpluscenter.com/item.as...name=hydraulic I use this picture for an example. The output's can be "tee'd" together.
I like the belt drive option, because the sprocket's could be changed for aplication to vary output, without expensive controller's?. Would this help with later in life leakage, for the motor's sake? Thank's for the link, Joe!
Some of the blackness in the hydraulic oil can be caused by heat!, But as fast as some of the pump's are turning? I wonder if they are cavitating? That could cause the funny wear pattern on the gear teeth.
Joe, I'm still trying to figure out an "unloader" to help with relief valve heat.
Still not finding what I want!
Well that's my long winded 2c worth!
Later, Neil#2 aka doodlebug.

[steamer]

Neil. I think your right, the biggest problem with this setup is there's no way to get rid of the heat. We'll have to ask Izzy to show us a better picture of the one he put in Travis's dozer. I'm not sure if he makes them or found them for sale. On Elliot's post for his ADT he has a picture up with a stand alone relief valve that looks well built. I've asked him to see if the manufacturer will sell them separately. Post #76 picture #9
http://rctruckandconstruction.com/sh...?t=1204&page=4
Rob

[doodlebug]

Hey Rob, I've been on the German site looking for answer's, couldn't get google to translate So I'll shoot some link's and maybe somebody can tell me what I'm doing wrong? I belong to this forum http://www.das-baumaschinen-forum.de...php?page=Index but I had to register to see anything, real fun, there is a hydraulik section, still need to translate. Lot's of pump discussion in it. I did learn that one of the member's is using simrit seals for hyd cylinder build's.
http://www.simritna.com/ I did find this on load sensing hydraulic's, http://www.microsofttranslator.com/b...1%2findex.html not much to go on yet. I think the guy use's an extra valve and contol's it with a servo and radio mixing, just guessing at this point, due to not enough info. Still trying to find more info to share!

And the Quest for the Holy Grail continue's Later, Neil#2 aka doodlebug.

[pugs]

Once I get a pump built a standalone relief valve would be an easy next project.

I like the idea of a belt as well, just cause most of these motors are running so **** fast, if it could be geared down to around 3k rpms it would just be better for everything I think. Plus I'm thinking an all steel pump body and some different options as far as tanks and inputs etc.

Next time I order some tooling, I will be getting some stuff to make barbed fittings as well.

[JAMMER]

If you are looking for that pressure adjustment valve you can get from Vario. Ed

[Lil Giants]

I don't have much experience with brushless motors, is an esc the only way to control them? As in a brushed motor for a specific voltage could be turned on/off with a relay switch, no speed control needed.

With the esc's that are available nowadays & the choice of radios too, the rpm of the motor can be preset to whatever speed is recommended.

There are voltage regulators from Castle Creations that could be implemented into the rc system as well to control motor speed of any brushed/brushless motor.

Inline pump & motor vs stacked with a belt drive, space availability will decide that combination necessity... good to have options.

Personally, every hyd system I do in the future, the pumpdrive motor will be governed with an esc and that'll do alot to control unnecessary heat issues of oil flow running when it doesn't need to or atleast not as fast.

[fhhhstix]

Originally Posted by Lil Giants

Personally, every hyd system I do in the future, the pumpdrive motor will be governed with an esc and that'll do alot to control unnecessary heat issues of oil flow running when it doesn't need to or atleast not as fast.

Or you could put an oil cooler on it like the 1:1 for less money than a speed controller and not need the extra ch as well. In what machine would you need to stop the oil flow if the pump is not needed then the model is probly sitting still so why not just put it on a battle switch. With a dozer or a track loader I can see shutting the pump off while tracking the model to a different place to work but if the model is working such as leveling or digging dirt then you are constantly on the hyds so you shouldn't need to shut them down. If you are mixing the esc to other functions then isn't there a lag time between stick movement and actual movement if not that would mean the esc goes to full throttle as soon as it sees movement in the mixed stick so wouldn't a battle switch mixed the same way do the same thing. I know our bigger CAT excavators do this with an on demand pump but they have a lag time to them but they are also smother to operate a little less jerky. I guess I need to see one work close up not sure of the benefit of an esc over a simple battle switch.

Travis

[Lil Giants]

I've watched alot of the norwegians' videos of their dozers, end loaders, excavators, adts, ect; operation looks pretty smooth to me. The way they explained it to me is that pump motor is set to 10% continuous within the radio programming and whichever ch/valve it's mixed with, the more the servo throw - the faster the rpm of the pump motor, the two chs are variably mixed. You want full speed from the pump, move the stick for that valve function to it's full limit. Speed controlled pump saves batt power and decreases heating of the oil, the oil flows fast only when you command it to do so via the tx.

Use a 3 pos switch on tx, in combination with a battleswitch - off/10% throttle/full throttle

Without some volume of airflow thru the inners of the model, what good is an oil cooler ... add a fan = current drain.