| Abstract: | Axial stiffness of ball screws has great effects on accuracy of positioning,dynamic characteristic and transmission efficiency. Axial contact stiffness modeling of ball screws is the key problem in dynamic analysis of ball screws. Aiming at obtaining axial stiffness of ball screws considering microscopic fractal characteristics of contact surfaces,a new analytical method is proposed to estimate axial contact stiffness of ball screws and combine the minimum excess principle with Mandelbort( MB)fractal theory in this research. The minimum excess principle is employed to conduct normal stress analysis. And the Mandelbort fractal theory is adopted to obtain contact stiffness in ball screws. The effectiveness of the proposed method is validated by the self-designed experiment. The comparison between theoretical results and experimental results demonstrates that axial contact stiffness of ball screws could be obtained by the proposed method. |
