A spherical roller bearing featured two rows of inner roller elements which are tapered towards its end much like a wine barrel. This type of bearing is self-aligning and typically used where high shock or misaligned loads are common. Spherical roller bearings are comparatively expensive but generally have a longer life span than other bearing types. They are also available as heavy duty variants for use in high load applications. A spherical roller bearing not only can absorb high degrees of angular deviation but generally higher operational speeds as well.
Spherical roller bearings share a common basic design with straight and tapered roller bearings in that they consist of an inner ring, captive roller race, and outer ring. The main difference in the designs is in the roller set which consists of a double row of barrel shaped rollers typically held in a brass or stainless steel cage. This design allows the roller rows in a spherical roller bearing to run at different speeds, thereby enabling the bearing to absorb high levels of linear deviation. This feature effectively lends this design a combination of radial and thrust bearing characteristics, making it exceptionally robust.
Due to the relative complexity of the manufacturing process involved, spherical roller bearings are more expensive than other designs. They do, however, have longer service lives due to their inherently robust nature. These bearings are capable of running under extreme conditions with minimal lubrication for up to twice as long as conventional roller and ball bearings. Some spherical roller bearing variants may include perforated outer ring and oil groove features in their design to facilitate easier lubrication and further extending their longevity. In general, this extended lifespan — along with the savings on downtime for bearing replacement — justifies the extra costs involved in fitting this type of bearing.
Certain ranges of spherical roller bearing are available with heavy duty rollers and cages that are suitable for extreme demand applications such as vibratory screens. This kind of machinery makes short work of a conventional bearing due to the constant shock loading and linear deviation involved in its operation. In this sort of aggressive operational environment, the spherical roller bearing is the only type that delivers acceptable service life. This type of bearing can also be used at rotational speeds generally higher than those of other bearing designs. In some cases, this difference in limiting speed may be as high as 20 percent or more.