Roller bearings are cylindrical relative motion assistance tools that are employed in order to allow for the motion of one object relative to another. They are just one of many bearing varieties and are employed in a wide variety of contexts.
Bearings are important parts of many kinds of equipment. In any system where moving parts are involved, some kind of means by which friction can be reduced is necessary in order to allow for movement. In a bicycle, for example, without a bearing system to overcome the friction between the wheel and the axel on which it is mounted, a much greater amount of work would be required from the bicycle's operator in order to make it move. This is the basic task that bearings perform. Certain kinds of movement assistance require certain kinds of bearings. In many cases, a system of ball bearings mounted in a race is used for motion assistance. However, in cases in which ball bearings are not appropriate, there are several alternatives. Roller bearings are popular alternatives to ball bearings; they usually feature cylindrical rollers mounted in a ring shape and can be used to support both radial and axial loads. Roller bearings can be made out of many materials, the most common of which are steel and ceramic materials.
Roller bearings are often used in load-handling applications, such as on conveyor belt rollers. Roller bearings can also be used in wind turbines, rolling mills, machine tool spindles and transmissions. The bearing within the roller bearing mechanism has inner and outer races, which are grooves where the balls of the bearing rest. The race is normally formed to allow the balls to fit loosely in the groove. These balls allow the cylinder to turn freely. Roller bearing manufacturers offer many sizes of roller bearings, depending on their intended use. Roller bearings may range in size from ten millimeters in diameter to a few feet, and they may have load-carrying capacities of thousands of pounds. Although roller bearings are quite popular and cost-effective, they also have a few disadvantages. Abrasion, fatigue and pressure-induced welding of the bearing all can contribute to a shorter life span for the bearing. It is very important to keep the bearings properly lubricated in order to avoid degradation.