It is made up of two different sizes of liquid cylinders, which are filled with water or oil in the liquid cylinder. Water filled is called "hydraulic press"; oil filled is called "hydraulic press". There is a sliding piston in each of the two cylinders. If a certain pressure is added to the small piston, according to Pascal's law, the small piston passes this pressure through the pressure of the liquid to the big piston and top the big piston. The cross section area of the small piston is S1, and the downward pressure on the small piston is F1. As a result, the pressure of the small piston on the liquid is P=F1/SI, which can be transferred to all directions by the same size.
In a certain mechanical and electronic system, hydraulic principle relies on the static pressure of liquid medium to complete the backlog, transmission and amplification of energy, so as to realize the lightness, scientification and maximization of the mechanical function.
Using hydraulic principle, hydraulic transmission system can be constructed, and hydraulic control system can also be constructed.