Rolling element bearings are perhaps the most common form of bearing and operate by carrying a load by placing rolling elements, such as balls or rollers, in between two rings, known as races. A common type of rolling bearing is the cylindrical roller bearing, which, as their name implies, uses cylinders to reduce friction between moving parts.
There are many types and sizes of cylindrical roller bearings including tapered, needle and spherical. Most of these are single row bearings with a cage. The cage prevents the rolling elements from colliding into one another, which helps reduce friction, wear and prevents bind.
Unlike their spherical counterparts, cylindrical roller bearing’s larger surface area allows them to carry larger loads, but this means increased friction and lower operating speeds. As with other roller bearings, cylindrical roller bearings must always be subjected to a minimum load. This is particularly true if the bearings are to encounter higher speeds, high acceleration forces or rapid changes in load direction. Without proper load, inertial forces can cause the rollers to slide, rather than roll, along their races, causing damage.
Cylindrical roller bearings are commonly used in belt or gear-driven medium to large sized electric motors. The earliest known cylindrical bearings could have been the logs used by ancient civilizations to move large stone structures around.