Hydraulic cylinder

craigco · Sep 30, 2016

Does a hydraulic cylinder create more force extending then retracting, or vice versa? Or is it the the same either way?

J. Schwiebert · Sep 30, 2016

Extending> You have the area of the piston, when it retracts you need to subtract the are of the piston rod.

JD Seller · Sep 30, 2016

When extending the area effected by the pressure of the oil is larger so it has more force pushing. The diameter of the ram shaft reduces the area on the retracting side. There fore the force is reduce by the size of the rod.

Example using a 3 inch cylinder with a one inch rod. Hydraulic pressure of 2000 PSI:

Radius squared x 3.14 x pressure

(1.5 x 1.5) x 3.14 x 2000 = 14130 lbs. of force when pushing.

(1.5 x 1.5) x 3.14 = 7.065 square inches minus (.5 x.5) x 3.14 = 0.785 7.065 - .0785 = 6.28 6.28 x 2000 = 12560 lbs. of pulling force when retracting.

So you can see that the cylinder has 1570 lbs. less force when retracting.

John B. · Oct 1, 2016

JD seller said it correctly.

To simplify it I'll say this.

You have more surface area (square inches) on the piston for the oil to push on when it's extending. The other side of the cylinder piston has the ram or rod so you have less surface area on that side of the piston for the oil to push on so power is reduced.

Hydraulic cylinder

craigco

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J. Schwiebert

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JD Seller

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John B.

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