Spherical roller bearing

A needle roller bearing is a special type of roller bearing which uses long, thin cylindrical rollers resembling needles. Ordinary roller bearings’ rollers are only slightly longer than their diameter, but needle bearings typically have rollers that are at least four times longer than their diameter. Like all bearings, they are used to reduce the friction of a rotating surface. Compared to ball bearings and ordinary roller bearings, needle bearings have a greater surface area in contact with the races, so they can support a greater load. They are also thinner, so they require less clearance between the axle and the surrounding structure.

Tapered roller bearings are based on the observation that cones that meet at a point can roll over each other without slipping. In practice, sections of cones are used. Tapered roller bearings are separable into a cone assembly and a cup. The non-separable cone assembly consists of the inner ring, the rollers, and a cage that retains and evenly spaces the rollers. The cup is simply the outer ring. Internal clearance is established during mounting by the axial position of the cone relative to the cup, although preloaded installations without clearance are common.