What is the difference between needle roller bearings and cylindrical bearings

Depending on the application, bearings or needle and cage assemblies without inner rings can be selected. At this time, the journal surface and housing hole surface that match the bearings directly serve as the inner and outer rolling surfaces of the bearings. To ensure the same load capacity and operating performance as bearings with rings, the hardness, machining accuracy, and surface quality of the raceway surface of the shaft or outer housing hole should be similar to the raceway of the bearing ring.