Roller bearing cages are used to keep the rollers at equal distances. Thus, friction and heat generation is kept to a minimum, the load is distributed evenly and the rolling elements are kept intact.
Full complement or full spherical roller bearings come loose without a cage. Thus, more rolling bearing elements per roller can considerably increase the load capacity. However, they are not suitable for speeds greater than 300 rpm.
Depending on the requirements, which must comply with the respective type of rolling bearings, cages can be used in various types and comprised of different materials (steel, nylon, Peek, brass). The cage construction and the material used depend on several factors. Temperatures, rotational speeds, special demands (e.g. inclination of the bearings) or the construction within the roller bearing, decide the final design of the cage construction.