On a double-acting cylinder the push force (extension) exerted is
calculated by multiplying the piston area at the base of the rod by
the pressure acting on the piston area.
The pull force (retraction) is calculated by mutiplying the
annulus area on the rod end by the pressure acting on it.
The annulus is the difference between the total piston area and
the rod area.
To find the extension force of a cylinder, use the cylinder force formula:
PSI = Pressure (Pounds per Square Inch)
r = Radius
Piston Area = (Pi X r2)
To find the retraction force of a cylinder, use the
cylinder retraction force formula:
Retraction Force (lbs) = (Piston Area - Rod Area) x PSI
Example: For a double-acting cylinder with a piston radius
of 2 inches,
a rod radius of 1 inch, 2000 psi supplied to the base on extension,
and 2500 psi supplied to the rod end for retraction:
Extension Force = (3.1416 x 22) x 2000 psi
Extension Force = 25,132.8 lbs
Retraction Force = Annulus x 2500 psi
Annulus = (3.1416 x 22) - (3.1416 x 12) =
Retraction Force = 23,562 lbs
(rounded to the nearest 10,000th)