Influence of Inclination Error on Non Repetitive Run-Out of the Single Ball Bearing

Abstract

Generally, rolling bearings are fixed at both ends of a rotating axis and a reference target is provided to give allowable fixing error of the bearings as appropriate according to the category and application. The allowable fixing error of a spindle, in which high rotational accuracy is required, should be very small. However, there is no research report which investigates closely the relationship between the fixing error and the rotational accuracy. Thus, eventually, this research intends to clarify the relationship between them and this report describes the relationship between the inclination error in bearing unit and the non-repetitive run-out using small ball rolling bearing. Consequently, using a measuring equipment of rotational error for single ball bearing, it was made known that the amplitude of the ball-cage rotation becomes very large when the inclination error increases. Thus, the conclusions of this research are as follows. (1) When the inclination error increases, the amplitude of frequency of cage rotation becomes large even supposing that the inclination error is in an allowable range. (2) When the inclination error increases, the amplitude of the doubled frequency of cage rotation becomes prominent. (3) When the number of rolling elements becomes large, the increment of variation of rotational period for the ball-cage is small.