basic hydraulic cylinder question

[JimMorrissey]

Does a cylinder have equal pressure in both directions?

 

[RonR]

Yes, but no.

Pressure is the same on both sides, but the amount of work you can get out of a cylinder is different.

The piston side allows for less oil to displace against the face, so it has less force. The opposite side without the obstuctive piston, can apply more force.

The piston side should move faster also.

Unless I am wrong, and I'm sure someone will point it out....

Ron

 

[Pooh_Bear]

One side has more surface area, thus more force.
PSI * Surface Area in Square Inches = Pounds of Force
The cylinder rod on one side of the piston takes up some of surface area.

Pooh Bear

 

[3RRL]

I think the speed is a funtion of flow. I may be wrong on this, but if they have the same size inlets, they will function at the same speed?

 

[Pooh_Bear]

Speed is a function of flow and volume.
The side with the cylinder rod has less volume and will fill faster at the same flow rate.
Thus it will move faster.

Pooh Bear

 

[3RRL]

OK, thanks for clarifiying...

 

[dfkrug]

Now that you are thinking about the two different sides of
a DA cylinder, imagine if you apply the pressurized oil to
BOTH sides of the cylinder AT THE SAME TIME. This is
actually done in a so-called "regen" setup. The rod side
of the cylinder experiences less linear pressure, so the
piston moves in that direction. Regen is used where you
do not need much net force, as in dumping a loader bucket.
Dumping is faster under REGEN because one side of the
cylinder experiences increased volume of oil by adding
the exhaust flow of the rod side of the cylinder to the
pump flow.

 

[JimMorrissey]

OK, with that know.....What I want to do is come up with some kind of hydraulic scissor boulder grapper (for lack of a better name). It would function off front hydraulics attached to quick-attach plate and the hydro cylinder would be used to close the arms on the rock, then lift with the loader and release where needed. My system is 3K and it seems like it would work with the appropriate size cylinder. The cylinder would contract to close the scissor on the rock. This would allow me to lift and place large stones without leaving the seat of the machine.

 

[Dirthog]

the regeneration circuit is used so you do not cavitate a cylinder ie starve one side for oil it will not always make one side any faster than the other. But It will make sure there is no hesitation or excess air in the system

 

[Pooh_Bear]

If you have a double acting cylinder both sides will already have fluid in them.
Pressurizing one side would push fluid out of the other side.
Any other scenario means you have air in the system.

Pooh Bear