The automobile hub unit is developed on the basis of standard angular contact ball bearings and tapered roller bearings,which combined these two sets bearings as one to make it owns the advantages of good assembly performance, clearance adjustment can be omitted, light weight, compact structure, large load capacity,sealing bearings with pre-loaded grease , omission of external hub seals, and maintenance-free. It has been widely used in cars, and it has also been gradually expanded in trucks.