The influence analysis of geometry errors on the contact characteristics of ball screw mechanism

The influence analysis of geometry errors on the contact characteristics of ball screw mechanism, such as the contact deformation, contact angle, etc. is theoretically investigated. The results demonstrate that the negative geometry errors of the ball screw result in the decrease of the contact deformation on balls or guiding grooves, and when the negative errors reach certain value there is no contact between the balls and the groove. On the other hand, if geometry errors of the ball screw are positive, the contact deformation increases. If the error heights are assumed to be a normally random distribution, the contact deformation without geometry error is the average value of that in random error. Geometry errors also result in uneven contact load and the variance of contact angle. Among all kinds of raceway parameter errors, raceway radius error has the greatest influence on the contact angle among all parameters.