help please - which hydraulic pump

[ricm]

hi everyone,

I have been into R/C for a number of years but I am completely new to hydraulics. I am currently building a tipping semi-trailer, thinking of making it hydraulic as a simple installation for my first step. Everything needs to be self-contained within the trailer (pump/ oil tank/ etc) so I can use the existing wireless control installed in the prime mover.

The ram will be a multi-stage cylinder with only one port, so I think I need a reversible pump because I'm not planning on servo activated valve gear. Many of the pre-assembled pump/ motor combos seem to need 12V (Garden Trucking/ Wedico/ ScaleArt), but I'll be running 7.2V pack in the trailer due to voltage limits of some other electrical kit. I am comfortable to source an appropriate (gear)motor as long as I know what RPM is required. The extended ram will probably need around 80ml of fluid to fill it, so a pump flow rate of around 200 - 240ml per min flow rate to give a reasonable lift time 20 seconds or so. Looks like most of you guys use 10 - 12bar?

Can anybody recommend a suitable pump? Also how much extra should I allow for tank capacity to ensure no air gets in when the ram is fully extended?

Also any other advice welcome - eg. do I need a pressure relief valve? filter?



Also happy to consider any second hand stuff if anybody has stuff up for grabs.....

thanks everyone