Hydraulikas

Hydraulikas, or hydraulics, is the field of science and engineering that studies the behavior of liquids and the use of pressurized fluids to transmit, control, and convert power. It focuses on how fluids transmit force, how energy is stored and converted, and how systems are designed to perform work through fluid pressure and flow.

The core principles include Pascal's law, which states that pressure applied to a confined fluid is transmitted undiminished in all directions. In hydraulic systems, a pump creates flow and pressure that power actuators such as cylinders for linear motion or hydraulic motors for rotary motion. System power can be described by P = p · Q, with p as pressure and Q as flow rate. Fluids are typically oils chosen for viscosity stability, lubricity, and fire resistance, and the liquid is kept clean and at a controlled temperature.

A typical hydraulic installation comprises a reservoir, a pump, a network of valves, actuators, and piping, plus filters and heat exchangers. Common components include directional, relief, and flow-control valves, as well as accumulators for energy storage and shock damping. Circuits can be open-center or closed-center, with either fixed or variable displacement pumps and either proportional or servo valves for precise control.

Applications span construction equipment (such as excavators and loaders), industrial presses, aerospace and automotive systems, and various industrial and marine machines. Advantages include high force output at low speeds, smooth and precise control, and simple sealing requirements; disadvantages involve potential leaks, contamination sensitivity, energy losses, and the need for thermal management and maintenance.

Historically, hydraulic concepts emerged in the 17th century and matured into practical power transmission and actuation in the 19th and 20th centuries.