Uav bearings are usually of two types: rolling bearings and plain bearings. Rolling bearings also include deep groove ball bearings, aligning ball bearings, tapered roller bearings, etc., and plain bearings include sliding journal bearings, sliding plane bearings, etc. Among them, the rolling bearing can withstand greater load and speed, suitable for high-speed rotation bearing system; The plain bearing has better self-lubricating effect and is suitable for occasions where the load is small and the friction coefficient is low.