All About Tapered Roller Bearings
By: Sunny Ling
Tapered roller bearing is one important kind of roller bearings. Four basic components are combined in the design of it. Those are the cup (outer ring), inner ring, tapered rollers and a cage (rolling element retainer). The inner ring, rollers and cage are referred to as the cone assembly. The rings and rollers are designed to carry the load, while the cage is only intended to retain and space the rollers.
This kind of bearing is usually mounted in pairs in either a direct or indirect arrangement. The basic design of a tapered bearing allows it to carry both axial and radial load. Typically the greater the angle in the design of a tapered bearing the greater thrust load it has the potential to carry. The arrangement and spacing must be considered when resolving the forces for each pair of bearing sets.
When loads are acting through the individual components of a tapered roller bearing, most of them are transferred through the contact between the rolling surfaces of the cup raceway, roller, and cone raceway. Because of the slightly different angles of the cup and cone raceways, a small resultant force also develops between the roller ends and the large rib of the tapered bearing inner ring. This force seats the rollers providing positive guidance keeping the rollers aligned. A perfectly aligned bearing is ideal for maximum life and performance. The angle of misalignment for a tapered roller bearing is the difference between the axis of rotation of the cone assembly and the cup axis.
Tapered roller bearings have high speed effects. The speed limitations of them are dependent upon the permissible operating temperatures of the application and the capability of the lubrication system to effectively remove enough heat throughout its life. Other effects such as moments and centrifugal forces can reduce fatigue life at high speeds but are not taken into account in the basic rating life.
Undoubtedly, lubrication has a very close relationship with bearing products. Adequate lubrication includes having a sufficient amount and also the proper type of lubricant. It should also be free of contaminants. Adequate lubrication is necessary for meeting performance goals and is assumed to be included in the application according to the basic rating life calculations. The proper lubricant reduces friction and prevents wear by providing a particular thickness of film, which separates the bearing surfaces during operation.