Life of linear motion rolling guides:
Linear motion rolling guides will eventually wear out even under normal operaion due to rolling contact fatigue.
Namely, as long as they carry some load, rolling elements and the raceways of the outer ring, shaft, track, rail, slide unit, etc. will be damaged by flaking caused by fatigue and the loss of scaled fragments from their surfaces. Such rolling guide can no longer be used.
The life of linear motion eolling guide is defined as the total traveling distance accomplished before the first evidence of fatigue flaking appears on hte raceway of rolling element.
However, where a group of rolling guide units with the same material size construction and deat treatment are operated unit the above fatigue flaking appears under the same operating condetions, there will be uneven disposition in each life because the phenomenon of maretial fatigue appears somewhat random.
therefore, the life of rolling guides is figured by a statistical method. As the reliability of rolling guide is very important, it is not appropriate to select necessary rolling guide on the basis of their average life. It is necessary for practical purposes to consider a travel life which the majority of the celected rolling guide are assured of reaching. Such life is the rated life defined below.
Rated Life
The rared life is defined as the total traveling distance that 90% of a group of the same roling guides under the same condition can fun free from any marerial damage caused by rolling fatigue.
However, the rated life of the strole ball cage assembly is represented by the total number of revolutions.
