Longitudinal adjustable unit for seats, in particular in motor vehicles

A spindle guide nut (12) moves on a spindle (10) that is driven by a worm gear (14) with a bearing sleeve on both sides. A multi-part casing for receiving the worm gear and spindle has two casing sections (20,30) that are inserted into one another in the axial direction of the spindle. Each casing section has a plate (31) where bars (33) jut out on one side. One casing section encompasses the bearing sleeve of the worm gear by more than 180[deg] .