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RCP57
11-17-2011, 04:49 PM
Just wondering if anyone has tried using an internal gear pump to run their hydraulics?
Lil Giants
11-17-2011, 04:58 PM
Like a Jung pump?
RCP57
11-17-2011, 05:03 PM
No, like a motorcycle engine oil pump where one gear turns inside the other.
RCP57
11-17-2011, 10:40 PM
Like a Jung pump?

Sorry! I didn't realize that the Jung pumps had internal gears. I thought they were external spur gear pumps.

Does anyone know roughly what size the gears are??? I want to build my own pump(s) but I don't know if the gears I hope to use will pump enough oil.

Thanks for any help!

Reg
Lil Giants
11-17-2011, 10:58 PM
Lou has a Jung pump in his adt. We were looking at the insides when I was visiting him & Greg a few yrs ago, if memory serves me correctly, gears were about 1/2inch dia and maybe 1/4inch width, with approx 5 or 6mm shaft. I don't know what the inlet/outlet hole sizes were. :confused:

Jung rates their pump flow ccm/revolution. I think my 850 has a .3ccm/rev with a large brushless motor (guessing 10 000rpm) using a 1:2.5 belt drive reduction = 1200ccm or 1.2L/ min flow. With 4mm flow lines, except it's 6mm lines from the valve to the Y connections of the boom and from the Y to the paired boom cyls is 4mm.
RCP57
11-17-2011, 11:58 PM
Cool, The gears I have may work then. After hearing that I think that I will give it a try at least.

is the line size your refering to ID or OD?

Thanks again! I think your Vario's requirements are very close to what I will need given the size of both models.

Reg
Lil Giants
11-18-2011, 01:20 AM
I went to check the bits of hose I left over from the 850 build.
Inlet to the pump = 6mm ID
Outlet from pump to valve = 4mm ID
Valve to Y = 4mm ID
Twin returns from valve to tank = 4mmID
Everything else, including from valve to relief valve = 2.5mm ID (4mm OD)
The max press I run @ is 24-26bar. No leaks, no blown hoses, no blown soldered joints (so far) and I've been working the shyt out of it in this moist clay (as seen in my vids).

I don't recall measuring the dia of the cyl pistons, but I would guesstimate (again) about 20mm.
RCP57
11-18-2011, 09:24 AM
Thanks again for the info! I didn't know the plumming was that large. My cylinders should be done soon but we are just winging it so I don't know for sure if they will work correctly on the first go. At any rate I am a long way from trying this thing anyway!

Thanks

Reg
doodlebug
11-18-2011, 11:54 AM
Try this link to Jung. http://www.jung-fluid.de/mini.htm
Later, Neil.