Abstract: A dynamic model of linear guideway joint with ball screw is built by means of the linear stiffness of linear rolling guideway and the axial stiffness of ball screw and angular contact ball bearing, which can be calculated by using the Hertz Contact Theory of elastic mechanics, and related computer program for calculating the contact stiffness is developed. A vertical machining centre is selected as an example, the effect of cutting load on the dynamic stiffness of joint part is analyzed, and the dynamic characteristics of the entire machine tool with the joint stiffness considered are also discussed on the basis of finite element method. The analytical results show that it can not only overcome the shortcoming of the conventional method in without considering the effect of ball screw pair, but also appear clarity in physical concept and simplification in computation.

Key words: Ball screw, Dynamic stiffness characteristic parameters, Hertz contact theory, Joint of linear guideway