il (which requires a circulation system).
Required Maintenance for a Ball Screw
Backlash- the “lost motion” that comes from looseness in the drive train.
Ball Bearing- a chromium steel ball set to tight tolerances that support loads.
Ball Nut- the nut that rides a ball screw and uses recirculating ball bearings.
Ball Screw Shaft- a chromium steel shaft with helical grooves that house ball bearings to change rotational motion into linear motion.
Elastic Deformation- a changing in shape that is not permanent and will reverse on its own.
End Cap Nut- a style of nut that recirculates at the end, it is used to accommodate large and multiple start leads.
Grease- a lubricant that is not very viscous.
Lead- the linear distance traveled in one rotation.
Lead Error- the difference in the actual travel and the theoretical travel of the ball nut.
Lubricant- a substance that reduces friction between other objects.
Mounting Error- error caused from inaccuracies in mounting the screw in bearings, motors, ball nuts, etc.
Multiple Starting Threads- a screw that has more than one track, only applicable on large leads due to space restraints. Used to add more balls to large lead ball nuts.
Nominal Diameter- the diameter of the thread “tops;” the maximum diameter of the screw
Oil- a lubricant that is highly viscous
Pitch Circle Nut- a style of nut that recirculates the balls every rotation, good for small leads and small nut profiles
Pitch Diameter of Balls- the diameter created by connecting the centers of the ball bearings
Preload- the tightness of the nut to the shaft, caused from the elastic deformation of the parts involved.
Profile Ball Nut- the most common nut type, it uses tubes to recirculate the balls.
Root Diameter- the diameter made from the bottom of the screw, the thinnest point and used in life calculations
Seals- a device used to keep things in, out or both.