There are quite a few designs for ball screw recirculation systems to choose from. Take as an example the end cap return ball nut, which makes use of a small cap added to the base of the ball screw nut.
A ball screw assembly is usually fairly simple although they do have a number of small components. When everything is in order, the ball screw should work without any difficulties, as the various components move through the system.
Unfortunately ball screw assemblies can be affected by any miniscule pieces of dirt. If it happens that small pieces of dust or dirt become fixed inside the ball screw nut, this will obstruct the movement of the ball bearings. A primary cause of the efficiency levels of ball screw assemblies is that they do not suffer from significant frictional effects. Any blockage in the interior of the ball screw assembly will reduce the smoothness, raising the levels of friction and lowering the efficiency of the apparatus.
Wiper systems usually consist of tiny brushes which move across the threads of the ball screw nut, basically picking up any obstructions. Felt, brush or elastomer is common components of these wipers. There is of course a selection of wiper designs available to ball screw designers. Every design has a primary function however, that is to collect any items of dust that have made their way inside the ball screw assembly. The majority of wipers are manufactured from plastic, i.e. elastomer, and they are constructed in such a way as to generate friction. The friction will help the wipers collect any dust that is brushed by them. Some wipers also contain an additional felt wiper, which is used to lubricate the interior of the ball screw nut with either oil or grease. This design then has the plastic wipers clear the threads, while the felt wipers lubricate.
Wipers are useful to help improve the lifespan of a ball screw, and are most effective if the ball screw has the correct degree of maintenance.
