Roller screws

High performance driving solutions

Roller screws
Roller screws offer a performance level far beyond the capabilities of ball screws. They are well suited for heavy loads, high rotational speed, high linear speed, high acceleration (especially planetary roller screws), ultimate precision and rigidity, and for operation in harsh environments.

With roller screws, the application load is transmitted from the nut to the shaft through the barrel-shaped surfaces of all rollers. The total surface area of the contacts between the shaft, the rollers and the nut is substantially increased compared to the ball screw design, resulting in larger load carrying capacity and increased service life. All these surfaces are made from high grade hardened bearing steel and are precision ground for best surface finish and highest durability.

Two basic concepts of roller screws are available for different needs and applications:
  • Planetary roller screws: satellite threaded rollers operating without recirculation provide the highest level of robustness, load carrying capacity, speed and acceleration, service life and reliability for the ultimate driving performance. With this technology, SKF offers three main variants of planetary roller screws: The traditional SR family with rollers synchronized to the nut, the IR inverted type with roller synchronized to the shaft, and the HR Ultra-Power range with capabilities further increased compared to the SR range.
  • Recirculation roller screws: grooved rollers provide the ideal combination of load carrying capacity, possible small lead for fine resolution and positioning accuracy, axial stiffness for ultra-precision driving solutions. Thanks to the small lead or small helix angle, this technology can offer a low back-driving or even self locking ability, combined with low rolling friction.

The SKF in-house highly integrated manufacturing process, from soft machining to heat-treatment, grinding and assembly operations, enables the best possible quality and highest roller screw performance available. Beyond the standard range made from standard high grade bearing steel, SKF offers special executions including stainless steel, high temperature steel and coatings to overcome the most demanding applications.

Complete assemblies

For reduced delivery time, SKF operates quick service facilities in Europe and in North America, included are standard screw shafts, nuts and accessories plus most common sizes of planetary and recirculating roller screws. Under certain conditions of quantity and shaft design, SKF can deliver stock items of nuts and shafts, or nuts and shafts with shaft ends machined according to customer requirements or with support bearings already fitted onto the screw shaft. Please consult your SKF branch office for all options available with this service.