Planetary roller screws

Planetary roller screws SR/BR/PR

More and more industries are converting their actuation requirements to SKF planetary roller screws, benefiting from their high load capability, easy integration and control, and positive environmental impact.

SKF offers the largest range of planetary roller screws to cover the most demanding applications. Through the use of the latest machining equipment, SKF can offer planetary roller screws from very small to very large diameters, with a wide variety of lead.

Features and benefits

  • Shaft length up to 8 000 mm (please consult SKF for longer screws)
  • Standard lead precision G5 (ep=25µm/300mm) to G1 (ep=6µm/300mm)
  • High rotational speed depending on screw nominal diameter: N.d0 max = 160000
    (for example,  4100 RPM for screws with nominal diameter 39 or 8000 RPM for screws with nominal diameter 20 mm; could be higher for smaller size shaft. Please consult SKF)
  • Optional stainless steel material
  • Optional wipers
  • Optional support bearings
  • Many strong contact points for heavy load capacity and long service life
  • Planetary concept without recirculation, resulting in high reliability, low noise, and high speed capability
  • Rollers synchronized by toothed rings, resulting in exceptional behaviour in applications with frequent changes of direction
  • Rollers guided for even circumferential load distribution
  • No torque variation during changes of direction
  • Axial play or preloaded execution on request
  • Long lead up to 42 mm for high linear speed, up to 1.8m/s for a roller screw of 40 44x30 for example.
  • Very small lead down to 2,00 mm, combining high positioning accuracy with high load carrying capacity, high rigidity and high speed
  • High axial stiffness, further increased with preloaded versions
  • Easy nut disassembly from the shaft, if necessary
  • Ability to operate in contaminated environment with minimum loss of performance
  • Adaptable tooling for non-standard, left hand thread or special designs
  • Minimum torque requirements
  • No miniature parts to improve robustness and reliability
  • Availability of customized designs
Technical data
Nominal diameter
from 8 to 240 mm (HR roller screws included)
Lead
from 2 to 50 mm
Basic dynamic load capacity
up to 3 994 kN (HR roller screws included)
Basic static load capacity
up to 23387 kN (HR roller screws included)
Acceleration
up to 12 000 rad/s2 for standard planetary  roller screws. (for higher accelerations please consult SKF)

SRC cylindrical nuts with axial play
Nominal diameter
from 8 to 120 mm
Lead
from 2 to 42 mm
Basic dynamic load capacityup to 1 131 kN
Basic static load capacity
up to 4141 kN

SRF flanged nut with axial play
Centred flange

Nominal diameter
from 8 to 120 mm
Lead
from 2 to 42 mm
Basic dynamic load capacity
up to 1 131 kN
Basic static load capacity
up to 4141 kN

SRP flanged nut with axial play

Off-centred flange

Nominal diameter
from 21 to 120 mm
Lead
from 5 to 42 mm
Basic dynamic load capacity
up to 1 131 kN
Basic static load capacity
up to 4141 kN

BRC cylindrical nut with backlash elimination
Backlash elimination
by oversized rollers
Diameter
from 8 to 64 mm
Lead
from 2 to 36 mm
Basic dynamic load capacity
up to 452 kN
Basic static load capacity
up to 961 kN

BRF flanged nut with backlash elimination
Backlash elimination
by oversized rollers
Centred flange

Diameter
from 8 to 64 mm
Lead
from 2 to 36 mm
Basic dynamic load capacity
up to 452 kN
Basic static load capacity
up to 961 kN

BRP flanged nut with backlash elimination

Backlash elimination
by oversized rollers
Off-centred flange

Diameter
from 21 to 64 mm
Lead
from 5 to 36  mm
Basic dynamic load capacity
up to 452 kN
Basic static load capacity
up to 961 kN

PRU cylindrical nut with preload
Preloaded split nut for optimum stiffness

Nominal diameter
from 8 to 64 mm
Lead
from 2 to 36 mm
Basic dynamic load capacity
up to 249 kN
Basic static load capacity
up to 480 kN

PRK flanged nut with preload
Preloaded split nut for optimum stiffness

Centred flange

Nominal diameter
from 8 to 64 mm
Lead
from 2 to 42 mm
Basic dynamic load capacity
up to 249 kN
Basic static load capacity
up to 480 kN

Typical applications

  • Presses for plastic injection moulding and blow moulding
  • Electromechanical presses
  • Servo presses for assembly and fitting
  • Broaching machines
  • Large machine tool
  • Car assembly lines (spot welding, gluing, crimping, riveting etc.)
  • Factory automation (handling, assembly, manufacturing)
  • Off-highway vehicles
  • Oil and gas
  • Aerospace
  • Steel industry
  • Test benches
  • Electromechanical cylinders
  • And many other applications