Features: 1) No need for pre-load adjustment at assembly. After press-fitting of bearings, it is only necessary to tighten nuts to the specified torque. 2) Compactness and high performance of wheel axles. No need for parts such as spacers, thus minimizing axial space requirement, therefore, high rigid and short axles can be used. 3) No need for grease replenishment at assembly. 4) High productivity. The number of parts is reduced with simplifies assembly work. 5) Large load rating. The bearing can be simultaneously resistant to axial loads in both directions and large radial load. 6) Large moment stiffness.