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 the force with which the system will be able to operate.
To make this task easier for you, BRhydraulic has prepared a free cylinder force calculator. Thanks to it, you can calculate the theoretical pushing and pulling force in a few seconds without the need for manual unit conversion.
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 enter three key parameters into the calculator. Measure them accurately (preferably with a caliper):
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Operating pressure (bar): The oil pressure in the hydraulic system powering the cylinder. This is usually determined by the parameters of the hydraulic pump or relief valve.
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Internal cylinder / piston diameter (mm): Measured inside the cylinder's "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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Rod diameter (mm): The external diameter of the chrome rod that extends from the cylinder.
After clicking "Calculate Force," the tool will provide results in kilograms (kgf), which helps in practically visualizing the machine's lifting capacity.
Theory: How do we calculate the force of a hydraulic cylinder?
If you want to understand the physics behind our calculator, the basic principle of fluid power hydraulics is based on Pascal's law. The force generated by a cylinder is directly proportional to the fluid pressure and the area on which that pressure acts.
The general formula for force is as follows:
F = p * A
Where:
- F – force
- p – operating pressure
- A – working surface area
Why is pulling force always less than pushing force?
When extending (pushing), the oil acts on the entire piston area (A1). The formula for the pushing surface area, where D is the piston diameter, looks like this:
A1 = (π * D²) / 4
When retracting the cylinder (pulling), oil is pushed from the other side. Here, however, the rod occupies space. The oil can only act on the so-called annular surface area (A2). We must therefore subtract the rod's surface area (d) from the piston's surface area:
A2 = [π * (D² - d²)] / 4
Since A2 is less than A1, 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 machine operating conditions (e.g., in excavators or front-end loaders), mechanical losses affect the final force.
Cylinder efficiency is typically 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 resistance of pins and bearings.
Build a reliable system with BRhydraulic
Do you know your system's parameters? Remember that even the best-calculated cylinder will not work at full power if the other components fail. In the BRhydraulic online store, you will find everything you need for building and servicing machinery:
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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-to-use cylinders with various strokes and diameters, ready for work in the toughest conditions.
- CETOP blocks: Modular connection plates and blocks that facilitate the construction of compact and efficient hydraulic systems.
Having trouble choosing an actuator for your machine? Contact our team of experts – we'll be happy to help!
