Wheel hub bearings are components used in automobile axles to bear weight and provide guidance for the rotation of the wheel hub. They bear both axial and radial loads and are an important component of automobile load and rotation. The wheel hub bearing unit is developed on the basis of standard angular contact ball bearings and tapered roller bearings. It integrates two sets of bearings and has the advantages of good assembly performance, eliminating clearance adjustment, light weight, compact structure, large load capacity, pre installed lubricating grease for sealed bearings, omitting external wheel hub seals, and avoiding maintenance. It has been widely used in cars and has a trend of gradually expanding its application in heavy-duty vehicles.