Like the previous generation, the new bearings can achieve linear speeds of up to 5m/s and acceleration rates of up to 100m/s2. By optimising the raceway geometries and surfaces, SKF has raised their load ratings, while a sturdy new cage design, with fewer components than before, improves reliability. The higher load capacities mean that users can downsize their designs or increase their loadings.
The interaction of the new cage, a new raceway plate and ball recirculation with minimised friction, is said to ensure smooth operation with low noise levels.
A self-aligning version of the bearing can handle alignment errors of up to ±30 minutes of arc, without compromising the seals. These bearings can compensate for deviations in parallelism between a shaft and its housing bore caused, for example, by shaft deflections and mounting or manufacturing inaccuracies.
An SKF D-Series linear bearing showing the: cage (1); recirculation cap (2); double lip seal (3); ball bearings (4); raceway (5); and lubrication port (6)
The bearings are supplied ready-lubricated, cutting mounting and maintenance costs and increasing the bearings’ reliability, thanks to the precisely dosed amounts of grease that are applied. Many applications with double-lip seals will never need to be relubricated because their theoretical lubrication interval will be longer than the bearing life.
The new bearings, which were unveiled at the recent Motek show in Germany, are due to go on sale in the first half of 2014, and will eventually cover shaft diameters from 12–40mm.
