hydraulics

Hydraulics is the branch of science and engineering that uses liquids under pressure to transmit, control, and convert energy. In hydraulic systems a confined liquid, typically oil or water-based fluids, is pressurized to transmit force from a pump to actuators and other components, enabling powerful and controllable motion.

The operation rests on Pascal's law, which states that pressure applied to an enclosed fluid is transmitted undiminished in all directions. This allows a relatively small input force to generate a much larger output force, as seen in hydraulic presses. Fluids in these systems are chosen for incompressibility, lubricating properties, and suitability for operating conditions. Pressure levels in hydraulic circuits are measured in megapascals and can range from modest values to high-pressure networks for demanding industrial tasks.

Key components include a reservoir, a pump, a network of tubes and hoses, control valves, actuators (hydraulic cylinders for linear motion and hydraulic motors for rotary motion), filters, and accumulators that store energy. The system’s speed and force are governed by flow rate and valve settings. The performance and efficiency depend on fluid viscosity, temperature, leakage, and component wear.

Applications span construction equipment, automotive brakes and steering, machine tools, aviation flight control systems, water and dam gate automation, and industrial presses. Advantages include high power density, smooth and precise control, and scalable force transmission. Limitations involve potential leaks, contamination, fire hazards with oil-based fluids, and the need for regular maintenance and proper system design to ensure safety and reliability.