Hydro-Dynamic Bearing, abbreviated as HDB, is a type of bearing used in fans that are part of complete water cooling sets. Its principle lies in separating rotating parts with a thin layer of liquid, usually oil. During the rotation of the fan shaft, pressure is generated in the liquid, which centers the shaft and prevents direct contact between metal surfaces. This reduces friction and wear, leading to a longer fan lifespan. Simultaneously, this technology contributes to quieter operation, as the oil layer effectively dampens vibrations.