Volvo EC300D

[steamer]

Reg, the only suggestion that I would make is to change from the round actuators on the spools to leavers. If you stagger the height of the arms then you could run every other spool with two servos on each side instead of direct drive. Then make the arms as long as needed to get the torque to move the valves. Hope this makes sense.
Rob

[JAMMER]

Could your problem be something simple like come in the side and go out the top. You have every thing coming in the top and out the top and that seems to load the valve on one side and binds it. Ed

[ihbuilder]

Reg , dumb ? , do your valves turn with ease with no pressure ? Could be just a little lapping needed . I have a Robbe valve that is tight like that till I loosen up the top .

[RCP57]

Originally Posted by ihbuilder

Reg , dumb ? , do your valves turn with ease with no pressure ? Could be just a little lapping needed . I have a Robbe valve that is tight like that till I loosen up the top .

The valves turn with very little resistance with no pressure. They actually turn decent when their open too, it's just when you are trying to open them from the fully closed position or close them from the open position that they are too stiff. Have you had your Robbe valve apart? Does it look much different than what we're doin? I think that Ed is right and it is side loading the plug. I have some of my grandfathers hydraulic books and in them it says that rotary valves are hard to balance but there has to be a way!


Thanks for the help guys!

I just recieved some parts for my Tigercat so....

[ihbuilder]

Reg , the Robbe valve is exactly what your doing . I'm thinking you have more pressure then you need . do you have a pressure relief valve in somewhere ? If not , put 1 on the supply circuit after the valve . come out where the plug is ( assuming thats the supply side of your valve ) I haven't got to play with the stuff from Richard yet , but I plan to make a solid base for the valves much like the verio setup . they bring the supply from the pump through the valve into a pressure relief valve of some sort ( needle valve I think ) .

[RCP57]

Originally Posted by ihbuilder

Reg , the Robbe valve is exactly what your doing . I'm thinking you have more pressure then you need . do you have a pressure relief valve in somewhere ? If not , put 1 on the supply circuit after the valve . come out where the plug is ( assuming thats the supply side of your valve ) I haven't got to play with the stuff from Richard yet , but I plan to make a solid base for the valves much like the verio setup . they bring the supply from the pump through the valve into a pressure relief valve of some sort ( needle valve I think ) .

Thats interesting to know that they are the same. I do have a relief valve and it's set at about 28 bar. At 20 bar this machine doesn't have a lot of power but the valves do turn much easier. I would like to be able to dig firm ground with it so I think 25-30 bar is necessary. Do you know the diameter of the valve?

Thanks Reg

[ihbuilder]

the ports under the rotor are .320" center to center . the rotor is .510" dia the crescents are the same as the ports . I'm going to build a 385cl cat which is as big as vario's 850 deere . I'm not sure these Robbe valves are big enough the ports seem to small for the flow needed ( about 1 mm dia ) I may be making my own .

Stevie