In both linear and/or rotary motion the purpose of a ball bearing is to reduce friction. Slides and bushings utilize various materials that tend to slightly reduce this friction problem. The ball bearing, however will outperform these devices and can reduce the coefficient of friction upwards of 100 times. The linear rotary bearing will offer this tremendous advantage in all directions of motion.
To take full advantage of this phenomenon, certain design considerations must be taken into account. Proper installation, lubrication and shaft characteristics will be discussed in the following paragraphs. Under "Design Considerations" shaft to bearing selection is emphasized. Because this is the world's first bearing to offer unrestricted linear rotary anti-friction motion, certain parameters should be considered.
If the linear motion is prominent, greater clearance between bearing and shaft is recommended. For example, a shaft classified as "A" with a precision or super precision bearing is acceptable. If the rotary motion is prominent, a class "B" Shaft is required with a precision or super precision bearing depending on the degree of precise rotary motion. If the rotary and/or linear motion requires a very high degree of precision, It is recommended that a "matched set" arrangement of shaft to bearing be considered. Here the bearing is matched to the shaft from line to line to within a few tenths (millimeters) depending on the diameter involved. Only in an extreme application would a press fit be suggested (as in the use of an "R" shaft). It should be noted again that the linear rotary bearing offers a considerable reduction in the coefficient of friction. It, therefore, has an extended life over such devices as bronze bushings, V-Ways and non-recirculating ball strips. Another factor to be considered is that, as the latter devices wear, their relative positioning is no longer accurate as initially aligned. "Down Time" is extremely costly and the consequences are obvious.