|Linear Ball Bearings|
Linear Ball Bearings, as their name implies, are linear bearings where the rolling contact is provided by hardened and ground balls. A linear ball slide is a compact form of linear bearing with a small form factor and a similarly short stroke. Maximum stroke can be a maximum of about one-third of the slide length, but the form factor justifies the stroke.
Cross Section of a Linear Ball Bearing Slide
In a three-quarters view of the slide shown in the following figure, additional preload block and attendant set screws are illustrated. The ball separator/retainer is also shown. Often the separator/retainer is made from a polymer for better lubricity and quieter operation. The set screws push or relieve the preload block so that the preload force of the rods on the balls is adjusted.
As can be seen in the drawing, linear ball slides support the balls with hardened and ground rods. Since hardened and ground rods and balls are common mechanical commodities, linear ball slides are inexpensive to manufacture. Another advantage of ball slides is that the point contact between the balls and the rods makes the assemblies self-cleaning. Debris is pushed out of the contact areas as a natural result of the configuration. The main disadvantage of ball slides compared to other linear bearings is that the point contact and multi-component construction gives them a low load capacity.