Hydraulic power pack

[General Lee]

Hi, Ive been toying with the idea of making my own power pack for a while now. I have a few bits got, but must do a bit of research on the subject so any bit of help is appreciated. Myself and a few mates made a log splittter for a college project years ago and I inherited it after the project was finished but i dont have a tractor to drive it so I want to make this.

What i have is a peugeot 1.9 diesal engine and a hydraulic pump off a tractor driven hedge cutter. I managed to get these parts off my neighbour as he was planning a similar project for his silage bale wrapper but instead purchased a proper one.

I know an air cooled engine would be ideal as it would be stationary but im sure with the proper coolant and the fans working properly it should keep cool.

I got a shaft made up and its to be bolted onto the fly wheel where it mates with the pump which is mounted on the gearbox housing.


I have a dual tank partially made, one half for diesal and the other for hydraulic fluid.

The pictures i have taken arent the best but they show the progress i have made so far. This has been in my shed for 2 years and i want to start at it again.

So some questions i would like to ask would be the best option for the hydraulic circuit. I know the pump has an inlet and outlet but what is the 3rd small port for on the pump? A friend said its for limiting the flow that exits the pump so it wouldnt flow at full pressurs when its turned on is he right? what kind of a valve would i need to control this? I could always blank it if its too much trouble.


My simple understanding of the circuit is this:

resevoir-filter-pump inlet-pump outlet- neutral on spool valve- return to tank
or- spool -ram


The spool i have doesnt as far as i know have a lock on position. The logsplitter is fully plumbed up and all it needs is is a supply but i want to incorporate a spool valve on the power pack incase it is ever used for something else. So can a way be devised to have the spool encorporated into the circuit without having to hold it forward to enguage the flow to the logsplitter. I wouldnt mind having multiple outputs like that of a tractor but would i be able to get the full force of the hydraulic pump by doing this.

Other things to be incorporated into the design would be safety pressure regulator to return fluid to tank when certain unsafe pressure is reached.



On another note im looking to put guages for oil and water temp onto a small control panal. Is it possible to get guages to work off the signals sent off the oem sensors or would new sensors have to be got?

Sorry for all the rambling put a little input from someone into hydraulics and electrics wouls be appreciated.

 

[drivewasher]

Just a guess but i would think the third port is pump by-pass to tank.
When a ram reaches its full stroke and stops the pump in theory would continue to pressurise the line causing damage. that pressure needs to be by-passed so an underloader inside pump would open letting the fluid out and back to the tank. When the ram is reversed the pressure that opened the by-pass valve drops slightly allowing fluid around the normal path as before.

All this time repairing pressure washers wasn't a waste then lol.... I hope..

 

[Shedendman]

[QUOTE All this time repairing pressure washers wasn't a waste then lol.... I hope..[/QUOTE]

You spent enough time working on DS's one
Hows it going steve

 

[pitmole]

Hi, the Dowty pumps are very hard to find seals for, they had internal rubber parts and they have been obsolete for years, so i hope it works ok. Some of them will only work if powered in one direction and wont like more than 2500 rpm, if it was a special for a pto drive then it wont be expecting more than 540 rpm and wont like your peugeot spinning it fast! The smaller port could be a pressure relief but i doubt it unless there is a built in pressure relief valve on it, more likely to be a case drain to tank or some sort of early load sense.

 

[General Lee]

Thank you drivewasher and pitmole some really good info on the pump. The pump is new off the shelf a couple of years ago and as far as i know and hasnt been used. The plastic caps are still on it. I'm gonna go into a hydraulic parts supplier tomorrow and seek some advice on the circuit i should be using

 

[General Lee]

I went into the hydraulic part suppliers today and he told me the pump was made in 1978!! the thing looked like new when i got it a few years ago. Must of been in stock somewhere for years. He said its a hydraulic motor and the 3rd plug is a drain to tank. If the motor gets a severe load it diverts the load back to tank to protect the motor. He said if i used it, it wouldnt make the pressure i would be after for a power pack and advised me to get a pump. I then was asking him how much they were and he said he could do a roquet pump for €250. I said i would have to think about it. I didnt get any spec's with pump he was selling I donno should i look for something second hand off a machine or buy that one.
I had a shaft made for the flywheel to fit the pump i have and ive the gearbox housing drilled to suit the mounting holes of the pump. So there will have to be some rework there if i was to get another pump.

 

[general--lee]

hey, dont know about pump but...........


thought id say hi as you got a cool name...

 

[Barking Mat]

An aged hydraulic pump shouldnt be a problem as long as they work, Ive worked with hydraulic marine transmissions, and you look like you need a quill shaft to link the damper plate (on the flywheel, no need for a clutch) to the pump shaft, then a plate across the old clutch housing to attatch the pump to prevent the pump from flying round, my understanding of the third pipe was a leak off, which when measured can give an indication as how worn the pump is. Be careful, at 2000 rpm a hydraulic pump like that can generate nearly 180 bar. Our hydraulic systems were fitted with a safety bypass valve, so if ever a propellor hit something instead of instantly generating huge pressure, it would bypass, hence saving the pipes etc... be careful with hydraulics.
If you look carefully at the electric sensor sender units, thyre often VDO and the values they work at are often indicated.

 

[General Lee]

I have the shaft to connect it to the flywheel made up and it bolts onto the gearbox housing so it wont spin. My problem is that i was told by the hyraulic suppliers that its a hydraulic motor not a pump and it wont make the desired pressure if worked in reverse. does anyone know what happens if i use it as a pump?


@ general--lee - Hi, Sorry didnt know there was another one using a similar name...