skruedrevet

Skruedrevet, or screw drive, is a term used in Norwegian technical terminology to denote a mechanism that converts rotational motion into linear motion via a threaded shaft and a nut. It encompasses a family of devices rather than a single invention and is found in many precision positioning and actuation applications.

Principle: The screw shaft carries a helical thread that mates with a corresponding nut or carriage. When the screw is rotated, the nut translates along the shaft by an amount equal to the thread pitch per revolution. The mechanism can be optimized for stiffness, speed, and load by selecting thread type, pitch, and bearing arrangement. Friction and backlash influence performance, with higher efficiency often achieved by rolling-element variants such as ball screws.

Variants: A leadscrew uses a constant pitch and typically exhibits self-locking behavior, whereas a ball screw substitutes rolling balls between thread and nut to greatly reduce friction and increase efficiency and precision. Common thread forms include Acme (trapezoidal) and square threads. Tolerances and lubrication are important for accuracy; backlash can be minimized with preloaded nuts.

Applications: Skruedrevet systems are widely used in machine tools for feed and positioning, CNC stages, clamping devices, linear actuators, robotics, aerospace and medical equipment, and anywhere precise linear motion is required.

History: The concept of converting rotation to linear motion via a screw dates to ancient times, with Archimedean screws and early machine tools incorporating leadscrews. Modern, precision screw drives were developed in the 18th–20th centuries, with ball screws becoming common in high-precision positioning in the mid-20th century.