For united needle and roller bearings for screw drives, they are accorded to reach very high cutting speeds while making sure the accuracy level requested for each function are met. Unitec SRB combined bearings makes use of static and dynamic stiffness for ballscrews.
The SRB bearings are needle roller bearings that has an outside ring with raceways for two axial cages and a broad inner ring, where the axial cages are in the middle.
The bearings can also provide a high degree of accuracy and stiffness, along with a development for the radial/axial support for accurate ball screws of machine tools. For the maximum stiffness to be reached, the bearings are preloaded by using a locknut.