Evaluation And Experimental Study On Accuracy Retention And Life Of Ball Screw

Aiming at the deficiency of the accuracy retentivity and life for precision ball screw, the basic theory of failure characteristics for ball screw in cyclic service period was researched. The measurement and control system was designed on the basis of the load simulation and online test bed. The optimization test scheme of accuracy stable ability and life was put forward. The theoretical basis, reasonable test equipment, detection method and data were researched to improve the precision retaining ability and life of the domestic ball screw pair.The failure pattern in cyclic service of the ball screw pair was analyzed. On this basis, the contact stress and movement of ball screw pair were analyzed. Considering the geometric parameter of the ball and the raceway of nut and screw and the coupling relationship between the pressure of the raceway and the variation of the contact angle, a precision loss model for precision ball screw was established by using the Hertz elastic contact theory and Archard theory. The contact fatigue properties were analyzed and life of ball screw was calculated.According to the mechanical structure design principle of the test-bed, combined with the requirements of the system control and test, the measurement and control system was completed. The dynamic measurement system software was written by Visual Basic, which realized movement and load control of the test-bed and dynamic measurement.On the basis of theoretical research and experimental equipment, according to the function of the test-bed, the relevant test method was improved. The experimental conditions and the parameters of measure were determined. Specific test plan and experimental steps were given. The calculation method of precision index and precision retaining ability and life assessment method were analyzed.Combining with the experiment plan for accuracy retentivity and life of ball screw, a certain nation-made ball screw reached P3 class was primary measured. The accuracy loss model was verified by contrasting the theoretical result with experimental data. It was proposed that the friction torque and noise auxiliary could give support to value accuracy retentivity and the influence of different pre-tightening force and velocity on accuracy retention was studied. The transmission efficiency of screw pair, not only the positive transmission efficiency but also the negative transmission efficiency, was analyzed.