Experiments Of The Ball Screw Failure Condition And Performance Of High Overload

Ball screw is an important linear transmission components for the space transmission system, however the ball screw often work in excess of the rated load at aerospace condition, so the failure modes of ball screw at aerospace condition will be different from at normal condition.Aim at high overload aerospace conditions, according to elastic-plastic mechanical theory and experimental research, the ball screw may be have five kinds of failure modes due to the large plastic deformation at contact points, namely:the severe plastic flows of raceway; larger gap between screw and nut; micro cracks on raceway surface; the fracture at top raceway; the ball stuck. According to a standard that the deformation of plastic do not more than the allowable values, the maximum allowable axial load was calculated. Taking the maximum permissible axial load as optimization goal, the geometrical constraints about the ball diameter, the contact angle and curvature ratio was established. Then the structure parameters was optimized by using optimization software.To verify the results of theoretical analysis and design optimization, the stiffness efficiency, carrying capacity and other properties of the paper ball screw were systematic comparative experimental studied for different structure parameters ball screw. The effect of parameters on the ball screw bearing capacity and overall performance was revealed. The results were basic verified about theoretical analysis. In order to enhance the ultimate capacity of ball screw, we found that refined the grain structure of raceway surface, reduce the surface roughness, the formation of surface residual stress by the way of rolling can improve the static load rating. The results were proved to be right by ball screw load test.