The sleeve is axially loaded by a compression spring. Plus, the sectioned nut has a lower integrity, and may be prone to excessive strain, especially in the torsional direction. Lubrication is pretty much required for ball screws if they are to have a reasonable life. Lead screw mechanisms involving bronze nuts need lubrication as well, and it is often a thick, damping grease. However, additional lubrication can increase the load capacity and extend the life.
Ball screws are prone to a certain amount of noise because of the ball bearing recirculation.
Radially preloaded lead screws employ axially sectioned nuts that are forced into the flanks of the screw for a close mesh. A common method presses the nut inward with a ramped sleeve loaded by a compression spring. The operating environment can sway the choice of material and style for the power screw. Lead screw configurations typically come in a stainless steel screw and plastic nut combination, or with a carbon steel screw and bronze nut. The stainless and plastic combination, which can do without lubrication, is highly corrosion resistant regardless, withstanding clean rooms, outdoor moisture, and so on.