Gradual Reliability Of Precision And Sensitivity Research Of Power Servo Tool Post

Power servo tool post is the core functional component of cnc turning center, its performance directly affects the quality of the machining. At present, such turret technology of China is still in its infancy, and related products are heavily dependent on import. Meanwhile, the power servo tool post is extremely demanding on the precision, but its core components-end gear trays-are always accompanied by wear phenomenon when they are translocating. Therefore, gradual reliability of precision and sensitivity research has important engineering significance. The main contents of paper are as follows:(1)Through the structure parameters of domestic production of power servo tool post are analyzed, uncertainty of measurement evaluation method is introduced, combined with requirements of relevant standards GB/T17421.2-2000, VDI/DGQ 3441 and JIS B 6330, mathematical model of unidirectional re-orientation accuracy and bidirectional re-orientation accuracy of turret transmission mechanism are established. Each factor of angular errors and backlash errors of gear transmission is considered, including machining or assembly errors caused by gears, shafts, bearings and other parts.(2)ANSYS is used for a certainty three-dimensional solid modeling of tool holder locking mechanism. Working out the range and type of distribution of input variables (including position errors and processing errors) of the finite element model utilize error synthesis theory and previous work.(3)experimental samples are taken by Optimal Latin Hypercube Design, and the results obtained then, a translocation deviation model of power servo tool post is established by BP neural networks technology, and its predictive values are compared with measured values. Iterative method is used to build a function relationship between re-orientation accuracy of power servo tool post and system parameters, and to predict the re-orientation accuracy of turret based on the model.(4)Archard model and three parameters gamma process is used to describe parameters deterioration process caused by wear of main parts of turret-end gear trays. According to re-orientation accuracy model of power servo tool post, precision state function is built. The perturbation method and the Edgeworth series is used for calculating the gradual reliability of precision and sensitivity of power servo tool post.By means of the optimizing of design parameters of the turret, its initial reliability has improved and recession of precision reliability has slowed. The basis for further improvement of its performance is provided.