Linear motion bearings are essential for guiding, driving and positioning equipment. The challenge for typical linear motion applications is that the bearing components need to provide high reliability over many cycles. They have two main components: shafts that act as a track to guide the linear movement, and nuts that grip and slide along the shaft.
Clean steel
To ensure that bearings deliver long life and high reliability, both the shafts and the balls or rollers in the nut are often made from clean steel. Clean steels are chemically identical to standard steels and have the same yield strength.
However, their fatigue strength is significantly higher, as they are produced under careful conditions which control the size, frequency and distribution of non-metallic particles called inclusions.
When forces are applied to a steel component, these tiny imperfections raise the stress in the material around them. These sites can become initiation points for cracks, which may propagate and ultimately lead to fatigue failure after many thousands of loading cycles...
Read the full article in DPA's November issue