A needle roller and cage assembly includes needle rollers and a cage that guides and retains the rollers. ¡These assemblies use both the shaft and housing as raceway surfaces. Consequently, the cross-sectional thickness of the assembly is small, roughly equivalent to the diameter of the needle rollers. ¡Because this bearing type has no inner or outer rings, the installation is much easier. ¡These assemblies are available in both singlerow and double-row configurations. ¡As long as the tolerance limits of the shaft and housing are satisfied, the bearing radial internal clearance can be adjusted.

Needle roller bearings have relatively small diameter cylindrical rolling elements whose length is much larger than their diameter. Compared with other types of rolling bearings, needle roller bearings have a small cross-sectional height and significant load-bearing capacity and rigidity relative to their volume. Also, because the inertial forces acting on them is limited, they are an ideal choice for applications with oscillating motion. Needle roller bearings also work well in compact and lightweight machine designs and they serve as a ready replacement for sliding bearings.