Learn in the textbookActuators and Device Control
DefinitionA hydraulic cylinder (油圧シリンダ) is an actuator that pushes a piston with the pressure of oil fed into a tube, producing linear motion.
ExplanationOil barely compresses, so even a small unit can deliver great force and hold a chosen position accurately. It is used, for example, in the arms of construction machinery that lift heavy loads and in press machines.
AnalogyIt works like pushing a syringe plunger with liquid: the plunger drives straight ahead with great force.
Memory hookThe Japanese name 油圧 combines "oil" and "pressure," telling you exactly what does the pushing; the English "hydraulic" likewise points to liquid.