Page 18 of Roller Bearings by RBC Bearings

technical data 1 introduction the methods equations and technical data presented in this section should be sufficient to select the correct bearings and estimate their performance for a wide range of applications for applications with severe or unusual operating conditions rbc is prepared to provide an in-depth analysis and recommend the most suitable bearing arrangement where standard bearings cannot be used rbc can meet the application requirements with a special bearing design specifically tailored for optimum performance 2 capacity and fatigue life of roller bearings dynamic capacity c [lbf,n or basic load rating for a roller bearing is that calculated constant radial load which a group of apparently identical bearings with a stationary outer ring can theoretically endure for a fatigue life of 106 revolutions of the inner ring static capacity co [lbf,n or static load rating is that uniformly distributed static radial load which produces a maximum theoretical contact stress of 4000 mpa 580,000 psi fatigue life l10 [rev hrs is a statistical measure of the life which 90 of a large group of apparently identical bearings will complete or exceed for a single bearing l10 also refers to the life associated with 90 reliability median life l50 is usually not more than five times l10 the relationship between rating life capacity and load is 1 2 the equations are valid in the range of approximately 100 hrs to 100,000 hrs of life at the low end extreme loads or speeds may adversely affect life at the high end metal fatigue may never be a factor in bearing service life 2.1 required bearing load capacity solving eq 2 for the dynamic capacity c we find 3 use for applications where a bearing must last a certain number of hours under given load and speed conditions normally bearings with rigidly mounted outer rings can support static loads up to the static capacity without detriment the static load limit may also be used to evaluate momentary shock loads in dynamic applications and the maximum load at very slow rotation or oscillation e.g 4 d is the bearing inside diameter [in 16

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