Page 2 of catalogue Ground ball screws of SKF Linearsysteme GmbH

Contents
The SKF brand now stands for more than ever before, and means more to you as a valued customer. While SKF maintains its leadership as the hallmark of quality bearings throughout the world, new dimensions in technical advances, product support and services have evolved SKF into a truly solutions-oriented supplier, creating greater value for customers. These solutions encompass ways to bring greater productivity to customers, not only with breakthrough application-specific products, but also through leading-edge design simulation Tools and consultancy services, plant asset efficiency maintenance programmes, and the industry’s most advanced supply management techniques. The SKF brand still stands for the very best in rolling bearings, but it now stands for much more. SKF – the knowledge engineering company

1 General....................................................................... 3 2 Recommendations...................................................... 4
Selection ......................................................................... Basic dynamic load rating......................................................... Static load carrying capacity..................................................... Critical rotating speed for screw shafts .................................. Permissible speed limit ............................................................. Efficiency and back-driving ...................................................... Axial play and preload ............................................................... Static axial stiffness of a complete assembly......................... Screw shaft buckling ................................................................. Manufacturing precision ........................................................... Materials and heat treatments ................................................ Number of circuits of balls ....................................................... Assembly procedure ......................................................... Radial and moment loads......................................................... Alignment .................................................................................... Lubrication .................................................................................. Designing the screw shaft ends............................................... Starting-up the screw............................................................... Operating temperature.............................................................. 4 4 5 5 5 6 6 7 7 8 8 8 9 9 9 9 9 9 9

3 Technical data ......................................................... 10
Lead precision according to ISO...................................... Geometric tolerance....................................................... Design and functional specifications ............................... Geometric profile of the track/ball area ............................... Preload ...................................................................................... Materials and thermal expansions........................................ Checking of the maximum axial operating load.................. Application of precision ball screw.................................. 10 11 14 14 14 15 16 17

4 Product information ................................................ 18
Ordering key .................................................................. PGFJ Flanged nut with internal preload, DIN standard ........ PGFL Double preloaded flanged nut long lead................. PGFE Double preloaded flanged nut ............................... PGCL Cylindrical double preloaded nut............................ Standard end machined ................................................. End bearings ................................................................. Product Inspection and certification ............................... How to orientate your choice.......................................... Calculation formulas ...................................................... 18 19 20 21 24 26 27 28 30 32

SKF - the knowledge engineering company...................... 36 2