Most rolling-element bearings are either ball or roller bearings. The roller bearing family consists basically of cylindrical, tapered, spherical, and needle bearings. Needle roller bearings are the smallest and lightest of the roller bearing family. That gives them specific advantages for certain applications, particularly those requiring reduced weight and space. The high roller length-to-diameter ratio helped give the bearings their name as well as their operating characteristics. Essentially, needle roller bearings have: • Higher load capacity than single-row ball or roller bearings of comparable OD.• The ability to handle a larger, more rigid shaft in a given application.• Excellent rolling characteristics within a small cross section.• Generally lower cost, especially for the drawn-cup type compared with machined versions. Needle rollers The most economical type of needle roller bearing is a full-complement of loose needle rollers assembled directly between a hardened and ground shaft and housing. Generally, hardened end washers provide axial location. This type appears in many applications such as those where a hardened and ground gear bore serves as the outer raceway. When application requirements are met and assembly is not difficult, a full complement of rollers forms a bearing of small cross section and high load capacity. It…
