Roller Screws

Example of a Roller Screw

SKF Roller Screws

In a ball screw the load is transmitted from the nut to the shaft through the balls engaged in the groove.

In a Roller Screw the load is transmitted from the nut to the shaft through the barrelled surfaces of all the engaged rollers.

There are two types of roller screw ~ planetary and recirculating.

Qualities of the planetary roller screw:

Many strong contact surfaces leading to a high load carrying capacity.
No recirculation and no contact between rolling elements enabling high rotational speeds.
The rollers are guides meaning no loss in preload torque when changing direction.
The timing mechanism gives exceptional reliability

Typical applications for planetary roller screws include; plastic moulding, valves, presses, machine tools, the steel industry, the tyre industry, automatic handling, military aircraft, tanks and the nuclear industry, amongst many others.

Qualities of the recirculating roller screw:

Very small leads providing fine resolution.
No miniature parts which means they’re simple and robust
Many strong contact surfaces leading to a high load carrying capacity

Typical applications for recirculating roller screws include; grinding machines, laboratory equipment, hospital equipment, paper making, and the printing industry amongst many others.

Why use a roller screw?

High load ratings ~ up to 1000 tonnes static
Very high rotational speeds
High acceleration and deceleration
Long life at high cycling rates
High reliability
Resistance to hostile environments
Ability to survive shock loads
Small displacements with excellent repeatability

Download the SKF Roller Screws catalogue