Re: A hydraulics question

"Robin S." wrote:

On Jun 17, 3:05 pm, Ned Simmons <n...@xxxxxxxxxx> wrote:

The diameter of the rod where it attaches to the piston is irrelevant.

I disagree, Ned.

Hydraulic force acts on surfaces which are perpendicular to the axis
of movement.

The only
thing that matters is the area of the portion of the rod that's moving in and
out of the pressurized chamber above the piston;

I don't understand why that would matter at all. The force has nothing
to do with the cylinder cap. The cylinder cap is not moving.

the area inside the sealing
gland in a normal cylinder. In other words, what you're concerned with is the
change in volume per unit distance travelled by the piston. Thinking about
where the mechanical advantage comes from in a hydraulic jack may help.

Volume in hydraulics determines the speed of the cylinder. Assuming
the pump can keep up, it has no effect on force. It is the pressure
created by the pump, and the area of the surface which is
perpendicular to the axis of motion in the cylinder (typically the
piston face).

Indeed, any area created by the OP's groove would be added to the
force calculation because it is perpendicular to the axis of movement.

Regards,

Robin

The groove has two sides, one adds pressure one adds it inversely,
cancelling the other out. The only way to increase the pressure is to
decrease the size of the rod going through the cap. This increases the
sectional area of the piston subject to the hydraulic pressure.

John
.

Relevant Pages

  • Re: A hydraulics question
    ... The diameter of the rod where it attaches to the piston is irrelevant. ... The cylinder cap is not moving. ... Volume in hydraulics determines the speed of the cylinder. ...
    (rec.crafts.metalworking)
  • Re: A few clutch-based questions.
    ... Should the slave piston "pop" out of the cylinder without any ... Not unusual if the master cylinder is sticky, ... so it's not only fluid pressure which makes them pop ...
    (uk.rec.motorcycles)
  • Re: A few clutch-based questions.
    ... Should the slave piston "pop" out of the cylinder without any ... Not unusual if the master cylinder is sticky, ... so it's not only fluid pressure which makes them pop out ...
    (uk.rec.motorcycles)
  • Re: temperature increases, volume decreases. why?
    ... >> Assume I have a gas in a cylinder that has a piston as a top. ... >> temperature inside the cylinder will increase, ... more collisions per minut means also that pressure got bigger. ...
    (sci.physics)
  • Re: Single mother in need of explanation
    ... I am by no means an expert on car engines but I believe the relevance ... What drives your car is a piston that moves up and down a cylinder. ... This causes a small explosion with a lot of pressure. ...
    (sci.physics.particle)