Hi,

I'm not sure I entirely understand your message, but solenoids are
almost always strongest at the very end of their travel. For a pull
solenoid, they are strongest when fully pulled in. For a push
solenoid, they are strongest when the output pin is fully extended.
Most solenoids are really just designed to hold something in position.
They cannot produce much force during mid-stroke.

I think you probably want an electric gearmotor with linear output to
push the hydraulic piston.

Sean


On Sat, Jan 9, 2010 at 7:38 PM, Electron <electron2k4@infinito.it> wrote:
>
> Hi all,
> this is really making me dumb.. hours and hours of Googling and reading
> datasheets, yet I have the doubt. :( In simple terms:
>
> I know solenoids are weaker in a part of the course/displacement and stronger
> in the other end. Physics tells me they should be stronger when energized and
> let them reach their final position, but datasheets seem to imply the opposite!
>
> I need a solenoid to push a idraulic piston. The force required is higher the
> more the piston is pushed, thus I need a solenoid that expresses/produces the
> maximum force when energized, not the other way round.
>
> Should I use the "push" type of solenoids, or do these produce the maximum
> force only at the begin of the course/displacement (i.e. right where they
> are when they're not powered)?
>
> Or should I use a pull type, and find a mechanical way to transform it into
> a push device?
>
> Or will push-pull type be more suitable?
>
> Or it definitely depends by the specific device? :P
>
> To make it even easier, what I really need is an electroactuated idraulic
> pump just like the one you see in motorbikes' brakes. Exactly like that, but
> electroactuated (and progressively so, even if via PWM).
>
> Thank You very much in advance for Your time.
> Mario
>
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