Selecting the right actuator for an agricultural, construction, or industrial machine requires precise calculations. Regardless of whether you are designing a new system or looking for a replacement for a damaged component, you need to know what force the system will be able to exert.
To make this task easier for you, BRhydraulic has prepared a free hydraulic cylinder force calculator. With it, you can calculate the theoretical pushing and pulling force in a few seconds without manually converting units.Hydraulic Cylinder Force Calculator
Calculate pushing and pulling force based on dimensions and pressure.
How to use the calculator? (Step-by-step instructions)
To get a correct result, you need to input three key parameters into the calculator. Measure them accurately (preferably with calipers):
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Working pressure (bar): The oil pressure in the hydraulic system powering the cylinder. This is usually determined by the hydraulic pump's parameters or the relief valve.
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Internal cylinder / piston diameter (mm): Measured inside the cylinder "tube". This is the diameter of the piston itself, against which the oil pushes. Note: do not confuse this with the external diameter of the cylinder!
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Piston rod diameter (mm): The external diameter of the chrome-plated rod that extends from the cylinder.
After clicking "Calculate Force," the tool will provide results in kilograms (kgf), which helps to practically visualize the machine's lifting capacity.
Theory: How do we calculate hydraulic cylinder force?
If you want to understand the physics behind our calculator, the fundamental principle of hydraulic power is based on Pascal's law. The force generated by a cylinder is directly proportional to the fluid pressure and the area over which that pressure acts.
The general formula for force is as follows:
F = p * A
Where:
- F – force
- p – working pressure
- A – working surface area
Why is pulling force always less than pushing force?
When extending (pushing), oil acts on the entire surface of the piston (A1). The formula for the pushing surface area, where D is the piston diameter, is as follows:
A1 = (π * D²) / 4
When the cylinder retracts (pulling), oil is pushed from the other side. However, here the piston rod (rod) occupies space. The oil can only act on the so-called annular area (A2). We must therefore subtract the piston rod area (d) from the piston area:
A2 = [π * (D² - d²)] / 4
Since it is smaller than it, the same pressure value will generate less force when pulling a load.
Actual cylinder efficiency – what to remember?
Our calculator provides theoretical values, assuming 100% system efficiency. In real-world machine operating conditions (e.g., in excavators or front loaders), mechanical losses affect the final force.
Cylinder efficiency is generally assumed to be 90-95%. This is due to:
- Friction of hydraulic seals (wipers, piston, and gland seals).
- Viscosity of the hydraulic oil used.
- Natural mechanical resistances of pins and bearings.
Build a reliable system with BRhydraulic
Do you already know your system's parameters? Remember that even the best calculated cylinder will not operate at full power if the rest of the components fail. In the BRhydraulic online store, you will find everything you need to build and service machines:
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Solenoid valves: Ensure precise control of oil direction and flow in your system.
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Cylinders: A wide selection of ready-made cylinders with various strokes and diameters, ready to work in the toughest conditions.
- CETOP blocks: Modular connection plates and blocks facilitating the construction of compact and efficient hydraulic systems.
Having trouble choosing a cylinder for your machine? Contact our team of experts – we'll be happy to help!
