Kulskruvar

Kulskruvar, known in English as ball screws, are devices used to convert rotational motion into precise linear motion with relatively high efficiency. The basic assembly consists of a threaded shaft and a ball nut in which steel balls circulate, rolling between the screw thread and the nut thread rather than sliding.

As the screw rotates, the balls circulate through a return path in the nut, allowing motion with low friction and reduced wear compared with traditional lead screws. This rolling contact provides higher load capacity and stiffness, enabling accurate positioning in demanding machinery.

Performance and design include both ground and rolled types; ground ball screws offer higher dimensional accuracy and surface finish, while rolled types are less expensive. Preloading the nut eliminates backlash, at the cost of higher preload and friction. Typical mechanical efficiency is high, often around 90% or more, depending on load and alignment.

Variants and accessories include single or double nut configurations, end supports, seals, and lubrication systems. Materials are usually steel alloys, with coatings to reduce wear. Lubrication with grease or oil is essential to minimize wear and extend life.

Applications for kulskruvar are widespread in CNC machine tools, robotics, aerospace actuators, precision stages, and other automated equipment where precise, repeatable motion is required. Maintenance and life depend on cleanliness, proper lubrication, and proper alignment; misalignment, contamination, or insufficient lubrication can increase wear or lead to premature failure. When properly designed and maintained, ball screws offer long service life and reliable performance in precision motion systems.