Kulskruv

Kulskruv, known in English as a ball screw, is a mechanical device that converts rotary motion into linear motion with high efficiency. It consists of a screw shaft with a helical groove and a matching nut that contains a recirculating assembly of hardened steel balls. As the screw turns, the balls roll between the grooves, producing precise linear displacement with low friction.

Operation and components: The ball bearings roll along the screw and nut grooves and return through a recirculation path, typically using return tubes or channels. Preload can be applied to eliminate clearance, improving stiffness and position accuracy. The assembly is lubricated and commonly built from steel, sometimes with surface coatings or polymer inserts to reduce wear and seal against contamination.

Advantages: Ball screws offer high efficiency, low friction, and substantial load-carrying capacity compared with traditional lead screws. They enable rapid, precise positioning and long service life, making them well suited for high-speed and high-precision applications such as computer numerical control machines, automation equipment, and robotics.

Disadvantages and considerations: They have higher upfront cost and greater mechanical complexity. Performance depends on proper lubrication, sealing, and alignment; they are more sensitive to contamination and require regular maintenance. In some configurations, the screw-nut system is designed to be non-self-locking, which affects how holding position is achieved without power.

Variants and applications: Variants include preloaded ball screws to reduce backlash and precision ball screws paired with sensors for closed-loop control. Widely used in machine tools, aerospace, semiconductor equipment, and automated machinery, kulskruv are chosen for applications demanding high accuracy and reliability.