Hydraulic Cylinder
A hydraulic cylinder is the actuator that converts pressurized oil into linear force and motion. The force it produces is the product of pressure and piston area: on an 80 mm bore piston, 200 bar gives about 10 tons of push. It consists of the barrel, piston, rod, sealing components, and end mountings.
The area calculation is the core of the matter. An 80 mm piston bore means about 50.3 cm2 of area; multiplied by 200 bar (about 204 kgf/cm2) this gives force on the order of 10,000 kgf. On the rod side, because the rod cross section is subtracted, force is lower and speed is higher at the same pressure.
- Sealing: the piston seal prevents internal leakage, the rod seal prevents external leakage. A thin film of oil on the rod is normal; dripping is not.
- Buckling: on long stroke cylinders the rod diameter is selected not only for force but also for buckling strength in the push direction.
- Cushioning: it is the internal restriction component that reduces the impact at the end of stroke.
In the field this knowledge turns into a fault distinction: if the rod slowly creeps back under load, either the piston seal is leaking internally or the load holding valve is not doing its job. Electronic lever control does not hide this leakage; you see the drift even when the command is at zero.
Where this term is used: What Is a Hydraulic Lever Retrofit Kit? Definition, Components, Operating Principle