What are needle roller bearings? What are the characteristics and performance of needle roller bearings?

Needle bearings are roller bearings with cylindrical rollers. Relative to their diameter, the rollers are thin and long. This type of roller is called a needle roller. The needle roller refers to the rotating body on the needle roller bearing. This type of bearing has a high load-bearing capacity and a compact radial structure. Despite its small cross-section, the bearing still has a high load-bearing capacity. Needle roller bearings are equipped with thin and long rollers (the roller length is 3 to 10 times the diameter, and the diameter is generally not more than 5mm), so the radial structure is compact. When its inner diameter size and load capacity are the same as those of other types of bearings, the outer diameter is the smallest, which is particularly suitable for support structures with limited radial installation dimensions.

Depending on the application, bearings without inner rings or needle roller and cage assemblies can be selected. In this case, the surface of the journal and the surface of the housing hole that match the bearing are directly used as the inner and outer rolling surfaces of the bearing. In order to ensure that the load capacity and running performance are the same as those of the bearing with rings, the hardness, processing accuracy and surface quality of the shaft or housing hole raceway surface should be similar to those of the bearing ring raceway. This type of bearing can only bear radial loads.