The main function of the truck hub bearing is to bear the load and provide precise guidance for the rotation of the hub. It bears both the axial load and the radial load, and is a very important component. The wheel hub bearing unit is developed on the basis of standard angular contact ball bearing and tapered roller bearing. It integrates two sets of bearings, which has good assembly performance, can omit clearance adjustment, light weight, compact structure and load capacity. The advantages of large, sealed bearings can be pre-loaded with grease, omission of external hub seals, and maintenance-free.