On the Starting Behavior of the Thrust Ball Bearing

The starting behavior of the thrust ball bearing is observed by the especially designed test apparatus. The following facts are found : (1) The compliance of the rotating angle with the rotating torque is shown by the complicated curve. (2) Owing to the shift of the initial relative position of the steel balls and races, considerable fluctuation of the starting torque is found. (3) The experimental relation between the starting torque and the thrust load is expressed by the equation M=kTn, n=1.37, k=0.081 (nonlubricating), k=0.051 (lubricating), where M: the starting torque (dyne-cm), T: the thrust load (g). The facts (1) and (3) are interpreted and discussed by the tangential elastic displacement and the interfacial slip at the area of contact between the steel ball and the rolling groove of the bearing race. On the cause of the fact (2), some discussion is made taking account of the state of the surface of the rolling groove.