Ball and roller screws
A traditional screw essentially consists of a steel shaft with trapezoidal thread and a bronze, metal or plastic nut. With this design, approximately 70% of the power is dissipated through the heat generated by friction at the sliding contact surfaces.
Unlike traditional screws, high efficiency screws from SKF are fitted with rolling elements (balls or rollers) that transmit the power between the nut and the screw shaft. The rolling motion minimizes friction between the nut and the shaft, therefore:
- the torque and power of the motor required to drive an application are much lower; depending on the design and technology, ball and roller screw efficiency is greater than 80%
- the wear rate is minimized
- the life of our products is much longer than the life of traditional sliding screws, and can be determined using rolling fatigue calculation
Due to the high efficiency of this technology, ball and roller screws are back-driving. Thus, some applications require a brake to prevent the carriage from falling down under its own weight.
Our comprehensive range of driving solutions includes precision rolled ball screws, ground ball screws and roller screws. Matching accessories for ball and roller screws such as nut flanges and support bearings are available.