Leadscrew

Spindles, sometimes called motion screws are machine elements that are used together with other elements in a helical gear to convert a rotational motion into a translational motion. Spindles consist of a threaded rod, that a cylindrical rod, in the case of simple application, a trapezoidal or flat thread is applied.

Ball screw spindles

When called ball screws, ball screw or even ball screws, linear motion is picked up at the threaded onto the spindle nut. For applications requiring high accuracy and backlash there are screws that hold a special thread and be paired with nuts where balls circulate in a closed system. These ballscrews occurs between spindle and nut, similar to a ball bearing, rolling friction, as opposed to sliding friction for spindles with flat and sharp threads.

Spindles are used in machine tools for longitudinal movement of the tool carriage, which carries the tool chuck or the workpiece chuck, the hand wheel or a gear transmission. Modern machine tools almost exclusively use ball screws with mutually braced ball nuts.

Also, the magnetic head in a disk drive is moved to a threaded spindle.

In automation, special machines units are used with ball screws for precise, partly dynamic positioning tasks. Complete units comprising a drive motor, linear guide and screw can also be combined in two or three dimensions. Such an arrangement in three dimensions can be found in a gantry robot application.

Screws that are used for example for occasional level settings of machines, have a similar function, but for cost reasons, the usual sharp thread of screws for fastening purposes.

Roller screw spindles

Roller screw spindles are used in roller screws. These screws are different with roller recirculation of the principle much like a ball screw drive works and the so-called planetary roller screw drive between the roller screw.

• Machine element
• Linear technology