So I built a hydraulic pump today

[RCP57]

I spent about 8 hours in the shop today and managed to make a hydraulic pump. It doesn't make a lot of pressure but I am just happy that it worked! Maybe the next one will perform better. http://youtu.be/ZWwlhNsWjiw








Thanks for looking!

[fhhhstix]

Good job with the pump. It may work just fine for a conversion. Hopefully your next attempt will produce more PSI but if not at least you can say you did it.


Travis

[RCP57]

Thanks, I got the motor and pump quite hot while trying to prime it before I decided to quickly make a tank that would gravity feed the pump. It only made 100 psi that way but when I took the misses out to the shop for a demo it had cooled down and went right up to 125 psi. I think I might be able to lap the two halfs of the body and reduce the end play in the gears but I'm not sure if it will gain much. I have one more pair of gears so now that I know that I can do it I may build on out of brass or steel. At least it wouldn't be as effected by heat soak then. At any rate it was a fun experiment(only because it kinda works) that cost less than $10 to build.

Reg

[Espeefan]

100 PSI is nothing to shake a stick at! For a first attempt, that's awesome.

[doodlebug]

Hey Reg, Way to go! Have you considered building a heat sink for the motor? http://www.amainhobbies.com/product_...FexAMgodlxYA4w Keep it up!
Cheer's, Neil.

[mazdaparts]

Would helical cut gears make any difference? Or would overdriving the gears change anything instead of direct drive.

[steamer]

Looking good Reg. Thanks for the BS session. Looking forward to the updates.
Rob

[Iron Art]

Reg, Don't you think that without flow that pump would be expected to generate a lot of heat and might not last long . Some type of open center solonoid valve or a relief valve would be the cure and I think the pump performance would be even greater than what you observed due to the cooler oil temp. You are on the right track with your design, Good JOB! Fred

[RCP57]

Originally Posted by Iron Art

Reg, Don't you think that without flow that pump would be expected to generate a lot of heat and might not last long . Some type of open center solonoid valve or a relief valve would be the cure and I think the pump performance would be even greater than what you observed due to the cooler oil temp. You are on the right track with your design, Good JOB! Fred

Yeah you are right Fred. I just wanted to quickly see if it worked last night so that was how I hooked it up. I dug through my fittings this morning and hooked it up with a relief valve. It doesn't pump any more pressure but at least the oil has somewhere to go. I also drilled out the inlet and outlet to a larger size and although it helped with volume it is still starving a little so I may open up the inlet side more if I can. I'll keep poking at it until I destroy it or get it to work right! At least it was a little bit successful so now I'm inspired to keep trying.

Well gotta get back to wrapping gifts...

Merry Christmas!

[RCP57]

http://youtu.be/2bQNXtrWiIA
I did a little tweeking to this today. I managed to get it to pump a little more pressure and quite a bit more volume. After opening up the ports I put it back on the mill and took a skim off the gear case. It seems to have helped as it makes 150+ psi for a short time and pumps 125psi steady without fading. I guess I won't be in the shop tomorrow but maybe if I was really good this year I will get something new to play with from Santa. If I get what I asked for then this pump will be just right....

Reg

[Lil Giants]

Using that machinist's playdo for a tolerance checker, not sure what it's called, but I've used it in the past when re bearing rod & crank journals.. it'd make it easy to measure your cover atop your gears.. the closer you get to zero, the better & more reliable your pressure will be.

The inlet port on my Jung is like 8mm (?) vs 4mm on the pressure side.

Good work on the pump.. you'll be our cdn manufacture of scale hyds in no time!

[Madda]

From where did you get the gears?

This looks very promising, I hope you get it running!

[RCP57]

Yeah Joe, I need to pick up some plasti gauge or something like that to see exactly how much clearence is still in there. I would like to make the inlet larger but the way I built this one it is hard to do. I guess I will have to try again with the knowledge I've learned from this one. I would love to build these for people like yourself but I think I have a lot to learn yet. You would be the perfect R&D person though...

Madda, The gears are cast iron and came from the private stash of an employee at a local hobby shop. I have two sets so I can built another pump and keep this one together.

Reg

[steamer]

Reg, Great progress. Got lots of volume now and it's starting to perform better. When you get the end clearance just right, it will be a winner for sure!
Rob

[RCP57]

Yeah thanks for the input Rob! A little more attention and it will work great or be ruined! Haha

Reg

[RCP57]

My in-laws bought me a really nice dial indicator for Xmas so that should help with accuracy.

[D8R]

My small experience from hydraulic pumps that has been dismantled is that there´s a realy tight fit inside where the gears are. Oil will find its way around if possible. Guess that the indicator can help you.
/Dan

[RCP57]

It should help with setting up the piece on the machine anyway. Unfortunately the rest is up to my ability to turn the handles:confuse d: I will try it again with a piece of steel soon. I have managed to get it to pump over 225 psi for a very brief period and 175 consistantly but the standard buna o ring can't take the strain. When I get a day off from work I will go to the local hydraulic shop in town and get some better o rings. If I could get this one to seal properly I think it would work well enough for a small model though.

Reg

[gauthib12]

great job on the pump, that is very good for a first go!! curious how did you seal the back where the motor goes?

Thanks,

[chaseracer]

impressive great job Reg!!!!!