Engine & Turbine Technology
cylindrical roller bearings. T ese bearings have no cage, the function of which is to guide the rolling elements and to maintain a set distance between them. T ese full complement bearings have the highest load ratings, since more rolling elements are fi tted to bearings that have no cage.
B
earings must deal with high dynamic forces, plus extreme
peak and minimum loads.
However, full complement roller bearings have relatively high friction because the rolling elements are in direct contact with each other. T ese kinematic conditions cause higher friction losses. In contrast, cylindrical roller bearings with conventional solid brass cages have signifi cantly lower friction, but often do not achieve the required load ratings due to the reduced number of rolling elements.
Ensuring low friction Schaeffl er has developed a new high capacity cylindrical roller bearing that incorporates a new sheet steel cage, which ensures low friction and provides suffi cient space for an additional rolling element in the bearing (due to very narrow crosspieces). T e cage comprises two cage rings lying one inside the other and joined together. T e crosspieces of the inner cage guide the rolling elements. At the same time, these retain the rolling elements in the bearing, even when the bearing ring is removed. T is means that the bearing is much easier to mount, as no separate device is required to help prevent the rolling elements from falling out. In addition, the special geometrical shape of the cage pockets improves lubricant fl ow, which reduces friction and prevents damage to the bearing. T e basic static and dynamic load ratings of the high capacity cylindrical roller bearing are 6% higher than those of a conventional cylindrical roller bearing with a solid brass cage. T is means that the rating life is increased by more than 20%. ●
Dr Steve Lacey is engineering manager at Schaeffler (UK) Ltd, Sutton Coldfield, West Midlands, UK.
www.schaeffler.co.uk
For more information ✔ at
www.engineerlive.com/ipe
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