Effect of ball size and lubricating condition on rolling fatigue life of the rolling bearing with small balls (part 1) - Rolling fatigue life under mixed lubricating condition -

Even if contact pressure is same, the basic rating life of rolling bearing with small contact areas is expected to be longer than that of ball bearings with larger contact areas. This is because rolling bearing damage is related to the numbers of non-metallic inclusions that pass through the volume under shear stress. Therefore, if the volume under shear stress is larger, the probability of damage is high. Conversely, if the volume under shear stress is smaller, the probability of damage is low. This is why the fatigue life of rolling bearing is thought to be affected by the contact area size. It has not yet been determined whether the fatigue life of rolling bearing is affected by the size of contact area, when ball and race contact under mixed-lubricating condition and damage to the contact surface. Accordingly, in this paper, the rolling fatigue life of the ball bearings with smaller balls and with larger balls were compared. And results are as follows. 1) Rolling fatigue life of rolling bearings isn't affected the contact area size. 2) It is possible to design the fatigue life of rolling bearings with small balls using the same design method as rolling bearings with ordinary balls.