Ball bearing is in the standard angular contact ball bearings and tapered roller bearings, developed on the basis of it will be two sets of bearing as a whole, has the assembly clearance adjustment performance is good, can be omitted, light weight, compact structure, large load capacity, for the sealed bearing prior to loading, ellipsis external wheel grease seal and from maintenance etc, and has been widely used in cars, In the heavy truck also has the gradual expansion application trend.