ruuviliikkeenä

Ruuvi liike, also known as a screw motion or screw thread motion, describes a type of mechanical movement that combines both rotation and translation along a single axis. Imagine turning a screw: as you rotate it, it simultaneously moves forward or backward into a material. This fundamental principle is ubiquitous in many mechanical systems.

The geometric relationship between the rotation and the linear translation in a screw motion is defined by the pitch of the screw thread. The pitch is the distance between adjacent threads. For a single-start screw, one complete rotation results in a linear movement equal to the pitch. For multi-start screws, the linear travel per rotation is a multiple of the pitch, determined by the number of starts.

This type of motion offers several advantages. It provides a mechanical advantage, allowing a small rotational force to generate a larger linear force, a principle used in jacks and vises. It also allows for precise control over linear positioning. The reversibility of screw motion is another key feature; applying a force in the linear direction can cause rotation.

Applications of screw motion are vast and include linear actuators, lead screws in machine tools for precise movement of workpieces or cutting tools, jacks for lifting heavy loads, vises for clamping, and even the basic mechanism of a ballpoint pen. Understanding screw motion is crucial for designing and analyzing many mechanical devices.